diff options
| author | Jonathan Corbet <corbet@lwn.net> | 2023-03-23 14:15:28 -0600 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2023-03-30 13:00:34 -0600 |
| commit | 1a2ac6d7ecdcde74a4e16f31de64124160fc7237 (patch) | |
| tree | 3d676da9f6598204197784cbfdd1a0f32e1adac3 /Documentation/arch | |
| parent | 87670c577041dc6d9daa1e39a3953002c6733d7f (diff) | |
docs: move sparc documentation under Documentation/arch/
Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy. Move
Documentation/sparc into arch/ and fix all in-tree references.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/arch')
| -rw-r--r-- | Documentation/arch/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/arch/sparc/adi.rst | 286 | ||||
| -rw-r--r-- | Documentation/arch/sparc/console.rst | 9 | ||||
| -rw-r--r-- | Documentation/arch/sparc/features.rst | 3 | ||||
| -rw-r--r-- | Documentation/arch/sparc/index.rst | 13 | ||||
| -rw-r--r-- | Documentation/arch/sparc/oradax/dax-hv-api.txt | 1433 | ||||
| -rw-r--r-- | Documentation/arch/sparc/oradax/oracle-dax.rst | 445 |
7 files changed, 2190 insertions, 1 deletions
diff --git a/Documentation/arch/index.rst b/Documentation/arch/index.rst index 208a8e67599c..8ec614488bd2 100644 --- a/Documentation/arch/index.rst +++ b/Documentation/arch/index.rst @@ -23,6 +23,6 @@ implementation. ../riscv/index ../s390/index ../sh/index - ../sparc/index + sparc/index x86/index xtensa/index diff --git a/Documentation/arch/sparc/adi.rst b/Documentation/arch/sparc/adi.rst new file mode 100644 index 000000000000..dbcd8b6e7bc3 --- /dev/null +++ b/Documentation/arch/sparc/adi.rst @@ -0,0 +1,286 @@ +================================ +Application Data Integrity (ADI) +================================ + +SPARC M7 processor adds the Application Data Integrity (ADI) feature. +ADI allows a task to set version tags on any subset of its address +space. Once ADI is enabled and version tags are set for ranges of +address space of a task, the processor will compare the tag in pointers +to memory in these ranges to the version set by the application +previously. Access to memory is granted only if the tag in given pointer +matches the tag set by the application. In case of mismatch, processor +raises an exception. + +Following steps must be taken by a task to enable ADI fully: + +1. Set the user mode PSTATE.mcde bit. This acts as master switch for + the task's entire address space to enable/disable ADI for the task. + +2. Set TTE.mcd bit on any TLB entries that correspond to the range of + addresses ADI is being enabled on. MMU checks the version tag only + on the pages that have TTE.mcd bit set. + +3. Set the version tag for virtual addresses using stxa instruction + and one of the MCD specific ASIs. Each stxa instruction sets the + given tag for one ADI block size number of bytes. This step must + be repeated for entire page to set tags for entire page. + +ADI block size for the platform is provided by the hypervisor to kernel +in machine description tables. Hypervisor also provides the number of +top bits in the virtual address that specify the version tag. Once +version tag has been set for a memory location, the tag is stored in the +physical memory and the same tag must be present in the ADI version tag +bits of the virtual address being presented to the MMU. For example on +SPARC M7 processor, MMU uses bits 63-60 for version tags and ADI block +size is same as cacheline size which is 64 bytes. A task that sets ADI +version to, say 10, on a range of memory, must access that memory using +virtual addresses that contain 0xa in bits 63-60. + +ADI is enabled on a set of pages using mprotect() with PROT_ADI flag. +When ADI is enabled on a set of pages by a task for the first time, +kernel sets the PSTATE.mcde bit for the task. Version tags for memory +addresses are set with an stxa instruction on the addresses using +ASI_MCD_PRIMARY or ASI_MCD_ST_BLKINIT_PRIMARY. ADI block size is +provided by the hypervisor to the kernel. Kernel returns the value of +ADI block size to userspace using auxiliary vector along with other ADI +info. Following auxiliary vectors are provided by the kernel: + + ============ =========================================== + AT_ADI_BLKSZ ADI block size. This is the granularity and + alignment, in bytes, of ADI versioning. + AT_ADI_NBITS Number of ADI version bits in the VA + ============ =========================================== + + +IMPORTANT NOTES +=============== + +- Version tag values of 0x0 and 0xf are reserved. These values match any + tag in virtual address and never generate a mismatch exception. + +- Version tags are set on virtual addresses from userspace even though + tags are stored in physical memory. Tags are set on a physical page + after it has been allocated to a task and a pte has been created for + it. + +- When a task frees a memory page it had set version tags on, the page + goes back to free page pool. When this page is re-allocated to a task, + kernel clears the page using block initialization ASI which clears the + version tags as well for the page. If a page allocated to a task is + freed and allocated back to the same task, old version tags set by the + task on that page will no longer be present. + +- ADI tag mismatches are not detected for non-faulting loads. + +- Kernel does not set any tags for user pages and it is entirely a + task's responsibility to set any version tags. Kernel does ensure the + version tags are preserved if a page is swapped out to the disk and + swapped back in. It also preserves that version tags if a page is + migrated. + +- ADI works for any size pages. A userspace task need not be aware of + page size when using ADI. It can simply select a virtual address + range, enable ADI on the range using mprotect() and set version tags + for the entire range. mprotect() ensures range is aligned to page size + and is a multiple of page size. + +- ADI tags can only be set on writable memory. For example, ADI tags can + not be set on read-only mappings. + + + +ADI related traps +================= + +With ADI enabled, following new traps may occur: + +Disrupting memory corruption +---------------------------- + + When a store accesses a memory location that has TTE.mcd=1, + the task is running with ADI enabled (PSTATE.mcde=1), and the ADI + tag in the address used (bits 63:60) does not match the tag set on + the corresponding cacheline, a memory corruption trap occurs. By + default, it is a disrupting trap and is sent to the hypervisor + first. Hypervisor creates a sun4v error report and sends a + resumable error (TT=0x7e) trap to the kernel. The kernel sends + a SIGSEGV to the task that resulted in this trap with the following + info:: + + siginfo.si_signo = SIGSEGV; + siginfo.errno = 0; + siginfo.si_code = SEGV_ADIDERR; + siginfo.si_addr = addr; /* PC where first mismatch occurred */ + siginfo.si_trapno = 0; + + +Precise memory corruption +------------------------- + + When a store accesses a memory location that has TTE.mcd=1, + the task is running with ADI enabled (PSTATE.mcde=1), and the ADI + tag in the address used (bits 63:60) does not match the tag set on + the corresponding cacheline, a memory corruption trap occurs. If + MCD precise exception is enabled (MCDPERR=1), a precise + exception is sent to the kernel with TT=0x1a. The kernel sends + a SIGSEGV to the task that resulted in this trap with the following + info:: + + siginfo.si_signo = SIGSEGV; + siginfo.errno = 0; + siginfo.si_code = SEGV_ADIPERR; + siginfo.si_addr = addr; /* address that caused trap */ + siginfo.si_trapno = 0; + + NOTE: + ADI tag mismatch on a load always results in precise trap. + + +MCD disabled +------------ + + When a task has not enabled ADI and attempts to set ADI version + on a memory address, processor sends an MCD disabled trap. This + trap is handled by hypervisor first and the hypervisor vectors this + trap through to the kernel as Data Access Exception trap with + fault type set to 0xa (invalid ASI). When this occurs, the kernel + sends the task SIGSEGV signal with following info:: + + siginfo.si_signo = SIGSEGV; + siginfo.errno = 0; + siginfo.si_code = SEGV_ACCADI; + siginfo.si_addr = addr; /* address that caused trap */ + siginfo.si_trapno = 0; + + +Sample program to use ADI +------------------------- + +Following sample program is meant to illustrate how to use the ADI +functionality:: + + #include <unistd.h> + #include <stdio.h> + #include <stdlib.h> + #include <elf.h> + #include <sys/ipc.h> + #include <sys/shm.h> + #include <sys/mman.h> + #include <asm/asi.h> + + #ifndef AT_ADI_BLKSZ + #define AT_ADI_BLKSZ 48 + #endif + #ifndef AT_ADI_NBITS + #define AT_ADI_NBITS 49 + #endif + + #ifndef PROT_ADI + #define PROT_ADI 0x10 + #endif + + #define BUFFER_SIZE 32*1024*1024UL + + main(int argc, char* argv[], char* envp[]) + { + unsigned long i, mcde, adi_blksz, adi_nbits; + char *shmaddr, *tmp_addr, *end, *veraddr, *clraddr; + int shmid, version; + Elf64_auxv_t *auxv; + + adi_blksz = 0; + + while(*envp++ != NULL); + for (auxv = (Elf64_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) { + switch (auxv->a_type) { + case AT_ADI_BLKSZ: + adi_blksz = auxv->a_un.a_val; + break; + case AT_ADI_NBITS: + adi_nbits = auxv->a_un.a_val; + break; + } + } + if (adi_blksz == 0) { + fprintf(stderr, "Oops! ADI is not supported\n"); + exit(1); + } + + printf("ADI capabilities:\n"); + printf("\tBlock size = %ld\n", adi_blksz); + printf("\tNumber of bits = %ld\n", adi_nbits); + + if ((shmid = shmget(2, BUFFER_SIZE, + IPC_CREAT | SHM_R | SHM_W)) < 0) { + perror("shmget failed"); + exit(1); + } + + shmaddr = shmat(shmid, NULL, 0); + if (shmaddr == (char *)-1) { + perror("shm attach failed"); + shmctl(shmid, IPC_RMID, NULL); + exit(1); + } + + if (mprotect(shmaddr, BUFFER_SIZE, PROT_READ|PROT_WRITE|PROT_ADI)) { + perror("mprotect failed"); + goto err_out; + } + + /* Set the ADI version tag on the shm segment + */ + version = 10; + tmp_addr = shmaddr; + end = shmaddr + BUFFER_SIZE; + while (tmp_addr < end) { + asm volatile( + "stxa %1, [%0]0x90\n\t" + : + : "r" (tmp_addr), "r" (version)); + tmp_addr += adi_blksz; + } + asm volatile("membar #Sync\n\t"); + + /* Create a versioned address from the normal address by placing + * version tag in the upper adi_nbits bits + */ + tmp_addr = (void *) ((unsigned long)shmaddr << adi_nbits); + tmp_addr = (void *) ((unsigned long)tmp_addr >> adi_nbits); + veraddr = (void *) (((unsigned long)version << (64-adi_nbits)) + | (unsigned long)tmp_addr); + + printf("Starting the writes:\n"); + for (i = 0; i < BUFFER_SIZE; i++) { + veraddr[i] = (char)(i); + if (!(i % (1024 * 1024))) + printf("."); + } + printf("\n"); + + printf("Verifying data..."); + fflush(stdout); + for (i = 0; i < BUFFER_SIZE; i++) + if (veraddr[i] != (char)i) + printf("\nIndex %lu mismatched\n", i); + printf("Done.\n"); + + /* Disable ADI and clean up + */ + if (mprotect(shmaddr, BUFFER_SIZE, PROT_READ|PROT_WRITE)) { + perror("mprotect failed"); + goto err_out; + } + + if (shmdt((const void *)shmaddr) != 0) + perror("Detach failure"); + shmctl(shmid, IPC_RMID, NULL); + + exit(0); + + err_out: + if (shmdt((const void *)shmaddr) != 0) + perror("Detach failure"); + shmctl(shmid, IPC_RMID, NULL); + exit(1); + } diff --git a/Documentation/arch/sparc/console.rst b/Documentation/arch/sparc/console.rst new file mode 100644 index 000000000000..73132db83ece --- /dev/null +++ b/Documentation/arch/sparc/console.rst @@ -0,0 +1,9 @@ +Steps for sending 'break' on sunhv console +========================================== + +On Baremetal: + 1. press Esc + 'B' + +On LDOM: + 1. press Ctrl + ']' + 2. telnet> send break diff --git a/Documentation/arch/sparc/features.rst b/Documentation/arch/sparc/features.rst new file mode 100644 index 000000000000..c0c92468b0fe --- /dev/null +++ b/Documentation/arch/sparc/features.rst @@ -0,0 +1,3 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. kernel-feat:: $srctree/Documentation/features sparc diff --git a/Documentation/arch/sparc/index.rst b/Documentation/arch/sparc/index.rst new file mode 100644 index 000000000000..ae884224eec2 --- /dev/null +++ b/Documentation/arch/sparc/index.rst @@ -0,0 +1,13 @@ +================== +Sparc Architecture +================== + +.. toctree:: + :maxdepth: 1 + + console + adi + + oradax/oracle-dax + + features diff --git a/Documentation/arch/sparc/oradax/dax-hv-api.txt b/Documentation/arch/sparc/oradax/dax-hv-api.txt new file mode 100644 index 000000000000..7ecd0bf4957b --- /dev/null +++ b/Documentation/arch/sparc/oradax/dax-hv-api.txt @@ -0,0 +1,1433 @@ +Excerpt from UltraSPARC Virtual Machine Specification +Compiled from version 3.0.20+15 +Publication date 2017-09-25 08:21 +Copyright © 2008, 2015 Oracle and/or its affiliates. All rights reserved. +Extracted via "pdftotext -f 547 -l 572 -layout sun4v_20170925.pdf" +Authors: + Charles Kunzman + Sam Glidden + Mark Cianchetti + + +Chapter 36. Coprocessor services + The following APIs provide access via the Hypervisor to hardware assisted data processing functionality. + These APIs may only be provided by certain platforms, and may not be available to all virtual machines + even on supported platforms. Restrictions on the use of these APIs may be imposed in order to support + live-migration and other system management activities. + +36.1. Data Analytics Accelerator + The Data Analytics Accelerator (DAX) functionality is a collection of hardware coprocessors that provide + high speed processoring of database-centric operations. The coprocessors may support one or more of + the following data query operations: search, extraction, compression, decompression, and translation. The + functionality offered may vary by virtual machine implementation. + + The DAX is a virtual device to sun4v guests, with supported data operations indicated by the virtual device + compatibility property. Functionality is accessed through the submission of Command Control Blocks + (CCBs) via the ccb_submit API function. The operations are processed asynchronously, with the status + of the submitted operations reported through a Completion Area linked to each CCB. Each CCB has a + separate Completion Area and, unless execution order is specifically restricted through the use of serial- + conditional flags, the execution order of submitted CCBs is arbitrary. Likewise, the time to completion + for a given CCB is never guaranteed. + + Guest software may implement a software timeout on CCB operations, and if the timeout is exceeded, the + operation may be cancelled or killed via the ccb_kill API function. It is recommended for guest software + to implement a software timeout to account for certain RAS errors which may result in lost CCBs. It is + recommended such implementation use the ccb_info API function to check the status of a CCB prior to + killing it in order to determine if the CCB is still in queue, or may have been lost due to a RAS error. + + There is no fixed limit on the number of outstanding CCBs guest software may have queued in the virtual + machine, however, internal resource limitations within the virtual machine can cause CCB submissions + to be temporarily rejected with EWOULDBLOCK. In such cases, guests should continue to attempt + submissions until they succeed; waiting for an outstanding CCB to complete is not necessary, and would + not be a guarantee that a future submission would succeed. + + The availablility of DAX coprocessor command service is indicated by the presence of the DAX virtual + device node in the guest MD (Section 8.24.17, “Database Analytics Accelerators (DAX) virtual-device + node”). + +36.1.1. DAX Compatibility Property + The query functionality may vary based on the compatibility property of the virtual device: + +36.1.1.1. "ORCL,sun4v-dax" Device Compatibility + Available CCB commands: + + • No-op/Sync + + • Extract + + • Scan Value + + • Inverted Scan Value + + • Scan Range + + + 509 + Coprocessor services + + + • Inverted Scan Range + + • Translate + + • Inverted Translate + + • Select + + See Section 36.2.1, “Query CCB Command Formats” for the corresponding CCB input and output formats. + + Only version 0 CCBs are available. + +36.1.1.2. "ORCL,sun4v-dax-fc" Device Compatibility + "ORCL,sun4v-dax-fc" is compatible with the "ORCL,sun4v-dax" interface, and includes additional CCB + bit fields and controls. + +36.1.1.3. "ORCL,sun4v-dax2" Device Compatibility + Available CCB commands: + + • No-op/Sync + + • Extract + + • Scan Value + + • Inverted Scan Value + + • Scan Range + + • Inverted Scan Range + + • Translate + + • Inverted Translate + + • Select + + See Section 36.2.1, “Query CCB Command Formats” for the corresponding CCB input and output formats. + + Version 0 and 1 CCBs are available. Only version 0 CCBs may use Huffman encoded data, whereas only + version 1 CCBs may use OZIP. + +36.1.2. DAX Virtual Device Interrupts + The DAX virtual device has multiple interrupts associated with it which may be used by the guest if + desired. The number of device interrupts available to the guest is indicated in the virtual device node of the + guest MD (Section 8.24.17, “Database Analytics Accelerators (DAX) virtual-device node”). If the device + node indicates N interrupts available, the guest may use any value from 0 to N - 1 (inclusive) in a CCB + interrupt number field. Using values outside this range will result in the CCB being rejected for an invalid + field value. + + The interrupts may be bound and managed using the standard sun4v device interrupts API (Chapter 16, + Device interrupt services). Sysino interrupts are not available for DAX devices. + +36.2. Coprocessor Control Block (CCB) + CCBs are either 64 or 128 bytes long, depending on the operation type. The exact contents of the CCB + are command specific, but all CCBs contain at least one memory buffer address. All memory locations + + + 510 + Coprocessor services + + +referenced by a CCB must be pinned in memory until the CCB either completes execution or is killed +via the ccb_kill API call. Changes in virtual address mappings occurring after CCB submission are not +guaranteed to be visible, and as such all virtual address updates need to be synchronized with CCB +execution. + +All CCBs begin with a common 32-bit header. + +Table 36.1. CCB Header Format +Bits Field Description +[31:28] CCB version. For API version 2.0: set to 1 if CCB uses OZIP encoding; set to 0 if the CCB + uses Huffman encoding; otherwise either 0 or 1. For API version 1.0: always set to 0. +[27] When API version 2.0 is negotiated, this is the Pipeline Flag [512]. It is reserved in + API version 1.0 +[26] Long CCB flag [512] +[25] Conditional synchronization flag [512] +[24] Serial synchronization flag +[23:16] CCB operation code: + 0x00 No Operation (No-op) or Sync + 0x01 Extract + 0x02 Scan Value + 0x12 Inverted Scan Value + 0x03 Scan Range + 0x13 Inverted Scan Range + 0x04 Translate + 0x14 Inverted Translate + 0x05 Select +[15:13] Reserved +[12:11] Table address type + 0b'00 No address + 0b'01 Alternate context virtual address + 0b'10 Real address + 0b'11 Primary context virtual address +[10:8] Output/Destination address type + 0b'000 No address + 0b'001 Alternate context virtual address + 0b'010 Real address + 0b'011 Primary context virtual address + 0b'100 Reserved + 0b'101 Reserved + 0b'110 Reserved + 0b'111 Reserved +[7:5] Secondary source address type + + + 511 + Coprocessor services + + +Bits Field Description + 0b'000 No address + 0b'001 Alternate context virtual address + 0b'010 Real address + 0b'011 Primary context virtual address + 0b'100 Reserved + 0b'101 Reserved + 0b'110 Reserved + 0b'111 Reserved +[4:2] Primary source address type + 0b'000 No address + 0b'001 Alternate context virtual address + 0b'010 Real address + 0b'011 Primary context virtual address + 0b'100 Reserved + 0b'101 Reserved + 0b'110 Reserved + 0b'111 Reserved +[1:0] Completion area address type + 0b'00 No address + 0b'01 Alternate context virtual address + 0b'10 Real address + 0b'11 Primary context virtual address + +The Long CCB flag indicates whether the submitted CCB is 64 or 128 bytes long; value is 0 for 64 bytes +and 1 for 128 bytes. + +The Serial and Conditional flags allow simple relative ordering between CCBs. Any CCB with the Serial +flag set will execute sequentially relative to any previous CCB that is also marked as Serial in the same +CCB submission. CCBs without the Serial flag set execute independently, even if they are between CCBs +with the Serial flag set. CCBs marked solely with the Serial flag will execute upon the completion of the +previous Serial CCB, regardless of the completion status of that CCB. The Conditional flag allows CCBs +to conditionally execute based on the successful execution of the closest CCB marked with the Serial flag. +A CCB may only be conditional on exactly one CCB, however, a CCB may be marked both Conditional +and Serial to allow execution chaining. The flags do NOT allow fan-out chaining, where multiple CCBs +execute in parallel based on the completion of another CCB. + +The Pipeline flag is an optimization that directs the output of one CCB (the "source" CCB) directly to +the input of the next CCB (the "target" CCB). The target CCB thus does not need to read the input from +memory. The Pipeline flag is advisory and may be dropped. + +Both the Pipeline and Serial bits must be set in the source CCB. The Conditional bit must be set in the +target CCB. Exactly one CCB must be made conditional on the source CCB; either 0 or 2 target CCBs +is invalid. However, Pipelines can be extended beyond two CCBs: the sequence would start with a CCB +with both the Pipeline and Serial bits set, proceed through CCBs with the Pipeline, Serial, and Conditional +bits set, and terminate at a CCB that has the Conditional bit set, but not the Pipeline bit. + + + 512 + Coprocessor services + + + The input of the target CCB must start within 64 bytes of the output of the source CCB or the pipeline flag + will be ignored. All CCBs in a pipeline must be submitted in the same call to ccb_submit. + + The various address type fields indicate how the various address values used in the CCB should be + interpreted by the virtual machine. Not all of the types specified are used by every CCB format. Types + which are not applicable to the given CCB command should be indicated as type 0 (No address). Virtual + addresses used in the CCB must have translation entries present in either the TLB or a configured TSB + for the submitting virtual processor. Virtual addresses which cannot be translated by the virtual machine + will result in the CCB submission being rejected, with the causal virtual address indicated. The CCB + may be resubmitted after inserting the translation, or the address may be translated by guest software and + resubmitted using the real address translation. + +36.2.1. Query CCB Command Formats +36.2.1.1. Supported Data Formats, Elements Sizes and Offsets + Data for query commands may be encoded in multiple possible formats. The data query commands use a + common set of values to indicate the encoding formats of the data being processed. Some encoding formats + require multiple data streams for processing, requiring the specification of both primary data formats (the + encoded data) and secondary data streams (meta-data for the encoded data). + +36.2.1.1.1. Primary Input Format + + The primary input format code is a 4-bit field when it is used. There are 10 primary input formats available. + The packed formats are not endian neutral. Code values not listed below are reserved. + + Code Format Description + 0x0 Fixed width byte packed Up to 16 bytes + 0x1 Fixed width bit packed Up to 15 bits (CCB version 0) or 23 bits (CCB version + 1); bits are read most significant bit to least significant bit + within a byte + 0x2 Variable width byte packed Data stream of lengths must be provided as a secondary + input + 0x4 Fixed width byte packed with run Up to 16 bytes; data stream of run lengths must be + length encoding provided as a secondary input + 0x5 Fixed width bit packed with run Up to 15 bits (CCB version 0) or 23 bits (CCB version + length encoding 1); bits are read most significant bit to least significant bit + within a byte; data stream of run lengths must be provided + as a secondary input + 0x8 Fixed width byte packed with Up to 16 bytes before the encoding; compressed stream + Huffman (CCB version 0) or bits are read most significant bit to least significant bit + OZIP (CCB version 1) encoding within a byte; pointer to the encoding table must be + provided + 0x9 Fixed width bit packed with Up to 15 bits (CCB version 0) or 23 bits (CCB version + Huffman (CCB version 0) or 1); compressed stream bits are read most significant bit to + OZIP (CCB version 1) encoding least significant bit within a byte; pointer to the encoding + table must be provided + 0xA Variable width byte packed with Up to 16 bytes before the encoding; compressed stream + Huffman (CCB version 0) or bits are read most significant bit to least significant bit + OZIP (CCB version 1) encoding within a byte; data stream of lengths must be provided as + a secondary input; pointer to the encoding table must be + provided + + + 513 + Coprocessor services + + + Code Format Description + 0xC Fixed width byte packed with Up to 16 bytes before the encoding; compressed stream + run length encoding, followed by bits are read most significant bit to least significant bit + Huffman (CCB version 0) or within a byte; data stream of run lengths must be provided + OZIP (CCB version 1) encoding as a secondary input; pointer to the encoding table must + be provided + 0xD Fixed width bit packed with Up to 15 bits (CCB version 0) or 23 bits(CCB version 1) + run length encoding, followed by before the encoding; compressed stream bits are read most + Huffman (CCB version 0) or significant bit to least significant bit within a byte; data + OZIP (CCB version 1) encoding stream of run lengths must be provided as a secondary + input; pointer to the encoding table must be provided + + If OZIP encoding is used, there must be no reserved bytes in the table. + +36.2.1.1.2. Primary Input Element Size + + For primary input data streams with fixed size elements, the element size must be indicated in the CCB + command. The size is encoded as the number of bits or bytes, minus one. The valid value range for this + field depends on the input format selected, as listed in the table above. + +36.2.1.1.3. Secondary Input Format + + For primary input data streams which require a secondary input stream, the secondary input stream is + always encoded in a fixed width, bit-packed format. The bits are read from most significant bit to least + significant bit within a byte. There are two encoding options for the secondary input stream data elements, + depending on whether the value of 0 is needed: + + Secondary Input Description + Format Code + 0 Element is stored as value minus 1 (0 evaluates to 1, 1 evaluates + to 2, etc) + 1 Element is stored as value + +36.2.1.1.4. Secondary Input Element Size + + Secondary input element size is encoded as a two bit field: + + Secondary Input Size Description + Code + 0x0 1 bit + 0x1 2 bits + 0x2 4 bits + 0x3 8 bits + +36.2.1.1.5. Input Element Offsets + + Bit-wise input data streams may have any alignment within the base addressed byte. The offset, specified + from most significant bit to least significant bit, is provided as a fixed 3 bit field for each input type. A + value of 0 indicates that the first input element begins at the most significant bit in the first byte, and a + value of 7 indicates it begins with the least significant bit. + + This field should be zero for any byte-wise primary input data streams. + + + 514 + Coprocessor services + + +36.2.1.1.6. Output Format + + Query commands support multiple sizes and encodings for output data streams. There are four possible + output encodings, and up to four supported element sizes per encoding. Not all output encodings are + supported for every command. The format is indicated by a 4-bit field in the CCB: + + Output Format Code Description + 0x0 Byte aligned, 1 byte elements + 0x1 Byte aligned, 2 byte elements + 0x2 Byte aligned, 4 byte elements + 0x3 Byte aligned, 8 byte elements + 0x4 16 byte aligned, 16 byte elements + 0x5 Reserved + 0x6 Reserved + 0x7 Reserved + 0x8 Packed vector of single bit elements + 0x9 Reserved + 0xA Reserved + 0xB Reserved + 0xC Reserved + 0xD 2 byte elements where each element is the index value of a bit, + from an bit vector, which was 1. + 0xE 4 byte elements where each element is the index value of a bit, + from an bit vector, which was 1. + 0xF Reserved + +36.2.1.1.7. Application Data Integrity (ADI) + + On platforms which support ADI, the ADI version number may be specified for each separate memory + access type used in the CCB command. ADI checking only occurs when reading data. When writing data, + the specified ADI version number overwrites any existing ADI value in memory. + + An ADI version value of 0 or 0xF indicates the ADI checking is disabled for that data access, even if it is + enabled in memory. By setting the appropriate flag in CCB_SUBMIT (Section 36.3.1, “ccb_submit”) it is + also an option to disable ADI checking for all inputs accessed via virtual address for all CCBs submitted + during that hypercall invocation. + + The ADI value is only guaranteed to be checked on the first 64 bytes of each data access. Mismatches on + subsequent data chunks may not be detected, so guest software should be careful to use page size checking + to protect against buffer overruns. + +36.2.1.1.8. Page size checking + + All data accesses used in CCB commands must be bounded within a single memory page. When addresses + are provided using a virtual address, the page size for checking is extracted from the TTE for that virtual + address. When using real addresses, the guest must supply the page size in the same field as the address + value. The page size must be one of the sizes supported by the underlying virtual machine. Using a value + that is not supported may result in the CCB submission being rejected or the generation of a CCB parsing + error in the completion area. + + + 515 + Coprocessor services + + +36.2.1.2. Extract command + + Converts an input vector in one format to an output vector in another format. All input format types are + supported. + + The only supported output format is a padded, byte-aligned output stream, using output codes 0x0 - 0x4. + When the specified output element size is larger than the extracted input element size, zeros are padded to + the extracted input element. First, if the decompressed input size is not a whole number of bytes, 0 bits are + padded to the most significant bit side till the next byte boundary. Next, if the output element size is larger + than the byte padded input element, bytes of value 0 are added based on the Padding Direction bit in the + CCB. If the output element size is smaller than the byte-padded input element size, the input element is + truncated by dropped from the least significant byte side until the selected output size is reached. + + The return value of the CCB completion area is invalid. The “number of elements processed” field in the + CCB completion area will be valid. + + The extract CCB is a 64-byte “short format” CCB. + + The extract CCB command format can be specified by the following packed C structure for a big-endian + machine: + + + struct extract_ccb { + uint32_t header; + uint32_t control; + uint64_t completion; + uint64_t primary_input; + uint64_t data_access_control; + uint64_t secondary_input; + uint64_t reserved; + uint64_t output; + uint64_t table; + }; + + + The exact field offsets, sizes, and composition are as follows: + + Offset Size Field Description + 0 4 CCB header (Table 36.1, “CCB Header Format”) + 4 4 Command control + Bits Field Description + [31:28] Primary Input Format (see Section 36.2.1.1.1, “Primary Input + Format”) + [27:23] Primary Input Element Size (see Section 36.2.1.1.2, “Primary + Input Element Size”) + [22:20] Primary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [19] Secondary Input Format (see Section 36.2.1.1.3, “Secondary + Input Format”) + [18:16] Secondary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + + + 516 + Coprocessor services + + +Offset Size Field Description + Bits Field Description + [15:14] Secondary Input Element Size (see Section 36.2.1.1.4, + “Secondary Input Element Size” + [13:10] Output Format (see Section 36.2.1.1.6, “Output Format”) + [9] Padding Direction selector: A value of 1 causes padding bytes + to be added to the left side of output elements. A value of 0 + causes padding bytes to be added to the right side of output + elements. + [8:0] Reserved +8 8 Completion + Bits Field Description + [63:60] ADI version (see Section 36.2.1.1.7, “Application Data + Integrity (ADI)”) + [59] If set to 1, a virtual device interrupt will be generated using + the device interrupt number specified in the lower bits of this + completion word. If 0, the lower bits of this completion word + are ignored. + [58:6] Completion area address bits [58:6]. Address type is + determined by CCB header. + [5:0] Virtual device interrupt number for completion interrupt, if + enabled. +16 8 Primary Input + Bits Field Description + [63:60] ADI version (see Section 36.2.1.1.7, “Application Data + Integrity (ADI)”) + [59:56] If using real address, these bits should be filled in with the + page size code for the page boundary checking the guest wants + the virtual machine to use when accessing this data stream + (checking is only guaranteed to be performed when using API + version 1.1 and later). If using a virtual address, this field will + be used as as primary input address bits [59:56]. + [55:0] Primary input address bits [55:0]. Address type is determined + by CCB header. +24 8 Data Access Control + Bits Field Description + [63:62] Flow Control + Value Description + 0b'00 Disable flow control + 0b'01 Enable flow control (only valid with "ORCL,sun4v- + dax-fc" compatible virtual device variants) + 0b'10 Reserved + 0b'11 Reserved + [61:60] Reserved (API 1.0) + + + 517 + Coprocessor services + + +Offset Size Field Description + Bits Field Description + Pipeline target (API 2.0) + Value Description + 0b'00 Connect to primary input + 0b'01 Connect to secondary input + 0b'10 Reserved + 0b'11 Reserved + [59:40] Output buffer size given in units of 64 bytes, minus 1. Value of + 0 means 64 bytes, value of 1 means 128 bytes, etc. Buffer size is + only enforced if flow control is enabled in Flow Control field. + [39:32] Reserved + [31:30] Output Data Cache Allocation + Value Description + 0b'00 Do not allocate cache lines for output data stream. + 0b'01 Force cache lines for output data stream to be + allocated in the cache that is local to the submitting + virtual cpu. + 0b'10 Allocate cache lines for output data stream, but allow + existing cache lines associated with the data to remain + in their current cache instance. Any memory not + already in cache will be allocated in the cache local + to the submitting virtual cpu. + 0b'11 Reserved + [29:26] Reserved + [25:24] Primary Input Length Format + Value Description + 0b'00 Number of primary symbols + 0b'01 Number of primary bytes + 0b'10 Number of primary bits + 0b'11 Reserved + [23:0] Primary Input Length + Format Field Value + # of primary symbols Number of input elements to process, + minus 1. Command execution stops + once count is reached. + # of primary bytes Number of input bytes to process, + minus 1. Command execution stops + once count is reached. The count is + done before any decompression or + decoding. + # of primary bits Number of input bits to process, + minus 1. Command execution stops + + + + 518 + Coprocessor services + + + Offset Size Field Description + Bits Field Description + Format Field Value + once count is reached. The count is + done before any decompression or + decoding, and does not include any + bits skipped by the Primary Input + Offset field value of the command + control word. + 32 8 Secondary Input, if used by Primary Input Format. Same fields as Primary + Input. + 40 8 Reserved + 48 8 Output (same fields as Primary Input) + 56 8 Symbol Table (if used by Primary Input) + Bits Field Description + [63:60] ADI version (see Section 36.2.1.1.7, “Application Data + Integrity (ADI)”) + [59:56] If using real address, these bits should be filled in with the + page size code for the page boundary checking the guest wants + the virtual machine to use when accessing this data stream + (checking is only guaranteed to be performed when using API + version 1.1 and later). If using a virtual address, this field will + be used as as symbol table address bits [59:56]. + [55:4] Symbol table address bits [55:4]. Address type is determined + by CCB header. + [3:0] Symbol table version + Value Description + 0 Huffman encoding. Must use 64 byte aligned table + address. (Only available when using version 0 CCBs) + 1 OZIP encoding. Must use 16 byte aligned table + address. (Only available when using version 1 CCBs) + + +36.2.1.3. Scan commands + + The scan commands search a stream of input data elements for values which match the selection criteria. + All the input format types are supported. There are multiple formats for the scan commands, allowing the + scan to search for exact matches to one value, exact matches to either of two values, or any value within + a specified range. The specific type of scan is indicated by the command code in the CCB header. For the + scan range commands, the boundary conditions can be specified as greater-than-or-equal-to a value, less- + than-or-equal-to a value, or both by using two boundary values. + + There are two supported formats for the output stream: the bit vector and index array formats (codes 0x8, + 0xD, and 0xE). For the standard scan command using the bit vector output, for each input element there + exists one bit in the vector that is set if the input element matched the scan criteria, or clear if not. The + inverted scan command inverts the polarity of the bits in the output. The most significant bit of the first + byte of the output stream corresponds to the first element in the input stream. The standard index array + output format contains one array entry for each input element that matched the scan criteria. Each array + + + + 519 + Coprocessor services + + +entry is the index of an input element that matched the scan criteria. An inverted scan command produces +a similar array, but of all the input elements which did NOT match the scan criteria. + +The return value of the CCB completion area contains the number of input elements found which match +the scan criteria (or number that did not match for the inverted scans). The “number of elements processed” +field in the CCB completion area will be valid, indicating the number of input elements processed. + +These commands are 128-byte “long format” CCBs. + +The scan CCB command format can be specified by the following packed C structure for a big-endian +machine: + + + struct scan_ccb { + uint32_t header; + uint32_t control; + uint64_t completion; + uint64_t primary_input; + uint64_t data_access_control; + uint64_t secondary_input; + uint64_t match_criteria0; + uint64_t output; + uint64_t table; + uint64_t match_criteria1; + uint64_t match_criteria2; + uint64_t match_criteria3; + uint64_t reserved[5]; + }; + + +The exact field offsets, sizes, and composition are as follows: + +Offset Size Field Description +0 4 CCB header (Table 36.1, “CCB Header Format”) +4 4 Command control + Bits Field Description + [31:28] Primary Input Format (see Section 36.2.1.1.1, “Primary Input + Format”) + [27:23] Primary Input Element Size (see Section 36.2.1.1.2, “Primary + Input Element Size”) + [22:20] Primary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [19] Secondary Input Format (see Section 36.2.1.1.3, “Secondary + Input Format”) + [18:16] Secondary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [15:14] Secondary Input Element Size (see Section 36.2.1.1.4, + “Secondary Input Element Size” + [13:10] Output Format (see Section 36.2.1.1.6, “Output Format”) + [9:5] Operand size for first scan criteria value. In a scan value + operation, this is one of two potential exact match values. + In a scan range operation, this is the size of the upper range + + + 520 + Coprocessor services + + +Offset Size Field Description + Bits Field Description + boundary. The value of this field is the number of bytes in the + operand, minus 1. Values 0xF-0x1E are reserved. A value of + 0x1F indicates this operand is not in use for this scan operation. + [4:0] Operand size for second scan criteria value. In a scan value + operation, this is one of two potential exact match values. + In a scan range operation, this is the size of the lower range + boundary. The value of this field is the number of bytes in the + operand, minus 1. Values 0xF-0x1E are reserved. A value of + 0x1F indicates this operand is not in use for this scan operation. +8 8 Completion (same fields as Section 36.2.1.2, “Extract command”) +16 8 Primary Input (same fields as Section 36.2.1.2, “Extract command”) +24 8 Data Access Control (same fields as Section 36.2.1.2, “Extract command”) +32 8 Secondary Input, if used by Primary Input Format. Same fields as Primary + Input. +40 4 Most significant 4 bytes of first scan criteria operand. If first operand is less + than 4 bytes, the value is left-aligned to the lowest address bytes. +44 4 Most significant 4 bytes of second scan criteria operand. If second operand + is less than 4 bytes, the value is left-aligned to the lowest address bytes. +48 8 Output (same fields as Primary Input) +56 8 Symbol Table (if used by Primary Input). Same fields as Section 36.2.1.2, + “Extract command” +64 4 Next 4 most significant bytes of first scan criteria operand occurring after the + bytes specified at offset 40, if needed by the operand size. If first operand + is less than 8 bytes, the valid bytes are left-aligned to the lowest address. +68 4 Next 4 most significant bytes of second scan criteria operand occurring after + the bytes specified at offset 44, if needed by the operand size. If second + operand is less than 8 bytes, the valid bytes are left-aligned to the lowest + address. +72 4 Next 4 most significant bytes of first scan criteria operand occurring after the + bytes specified at offset 64, if needed by the operand size. If first operand + is less than 12 bytes, the valid bytes are left-aligned to the lowest address. +76 4 Next 4 most significant bytes of second scan criteria operand occurring after + the bytes specified at offset 68, if needed by the operand size. If second + operand is less than 12 bytes, the valid bytes are left-aligned to the lowest + address. +80 4 Next 4 most significant bytes of first scan criteria operand occurring after the + bytes specified at offset 72, if needed by the operand size. If first operand + is less than 16 bytes, the valid bytes are left-aligned to the lowest address. +84 4 Next 4 most significant bytes of second scan criteria operand occurring after + the bytes specified at offset 76, if needed by the operand size. If second + operand is less than 16 bytes, the valid bytes are left-aligned to the lowest + address. + + + + + 521 + Coprocessor services + + +36.2.1.4. Translate commands + + The translate commands takes an input array of indices, and a table of single bit values indexed by those + indices, and outputs a bit vector or index array created by reading the tables bit value at each index in + the input array. The output should therefore contain exactly one bit per index in the input data stream, + when outputting as a bit vector. When outputting as an index array, the number of elements depends on the + values read in the bit table, but will always be less than, or equal to, the number of input elements. Only + a restricted subset of the possible input format types are supported. No variable width or Huffman/OZIP + encoded input streams are allowed. The primary input data element size must be 3 bytes or less. + + The maximum table index size allowed is 15 bits, however, larger input elements may be used to provide + additional processing of the output values. If 2 or 3 byte values are used, the least significant 15 bits are + used as an index into the bit table. The most significant 9 bits (when using 3-byte input elements) or single + bit (when using 2-byte input elements) are compared against a fixed 9-bit test value provided in the CCB. + If the values match, the value from the bit table is used as the output element value. If the values do not + match, the output data element value is forced to 0. + + In the inverted translate operation, the bit value read from bit table is inverted prior to its use. The additional + additional processing based on any additional non-index bits remains unchanged, and still forces the output + element value to 0 on a mismatch. The specific type of translate command is indicated by the command + code in the CCB header. + + There are two supported formats for the output stream: the bit vector and index array formats (codes 0x8, + 0xD, and 0xE). The index array format is an array of indices of bits which would have been set if the + output format was a bit array. + + The return value of the CCB completion area contains the number of bits set in the output bit vector, + or number of elements in the output index array. The “number of elements processed” field in the CCB + completion area will be valid, indicating the number of input elements processed. + + These commands are 64-byte “short format” CCBs. + + The translate CCB command format can be specified by the following packed C structure for a big-endian + machine: + + + struct translate_ccb { + uint32_t header; + uint32_t control; + uint64_t completion; + uint64_t primary_input; + uint64_t data_access_control; + uint64_t secondary_input; + uint64_t reserved; + uint64_t output; + uint64_t table; + }; + + + The exact field offsets, sizes, and composition are as follows: + + + Offset Size Field Description + 0 4 CCB header (Table 36.1, “CCB Header Format”) + + + 522 + Coprocessor services + + +Offset Size Field Description +4 4 Command control + Bits Field Description + [31:28] Primary Input Format (see Section 36.2.1.1.1, “Primary Input + Format”) + [27:23] Primary Input Element Size (see Section 36.2.1.1.2, “Primary + Input Element Size”) + [22:20] Primary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [19] Secondary Input Format (see Section 36.2.1.1.3, “Secondary + Input Format”) + [18:16] Secondary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [15:14] Secondary Input Element Size (see Section 36.2.1.1.4, + “Secondary Input Element Size” + [13:10] Output Format (see Section 36.2.1.1.6, “Output Format”) + [9] Reserved + [8:0] Test value used for comparison against the most significant bits + in the input values, when using 2 or 3 byte input elements. +8 8 Completion (same fields as Section 36.2.1.2, “Extract command” +16 8 Primary Input (same fields as Section 36.2.1.2, “Extract command” +24 8 Data Access Control (same fields as Section 36.2.1.2, “Extract command”, + except Primary Input Length Format may not use the 0x0 value) +32 8 Secondary Input, if used by Primary Input Format. Same fields as Primary + Input. +40 8 Reserved +48 8 Output (same fields as Primary Input) +56 8 Bit Table + Bits Field Description + [63:60] ADI version (see Section 36.2.1.1.7, “Application Data + Integrity (ADI)”) + [59:56] If using real address, these bits should be filled in with the + page size code for the page boundary checking the guest wants + the virtual machine to use when accessing this data stream + (checking is only guaranteed to be performed when using API + version 1.1 and later). If using a virtual address, this field will + be used as as bit table address bits [59:56] + [55:4] Bit table address bits [55:4]. Address type is determined by + CCB header. Address must be 64-byte aligned (CCB version + 0) or 16-byte aligned (CCB version 1). + [3:0] Bit table version + Value Description + 0 4KB table size + 1 8KB table size + + + + 523 + Coprocessor services + + +36.2.1.5. Select command + The select command filters the primary input data stream by using a secondary input bit vector to determine + which input elements to include in the output. For each bit set at a given index N within the bit vector, + the Nth input element is included in the output. If the bit is not set, the element is not included. Only a + restricted subset of the possible input format types are supported. No variable width or run length encoded + input streams are allowed, since the secondary input stream is used for the filtering bit vector. + + The only supported output format is a padded, byte-aligned output stream. The stream follows the same + rules and restrictions as padded output stream described in Section 36.2.1.2, “Extract command”. + + The return value of the CCB completion area contains the number of bits set in the input bit vector. The + "number of elements processed" field in the CCB completion area will be valid, indicating the number + of input elements processed. + + The select CCB is a 64-byte “short format” CCB. + + The select CCB command format can be specified by the following packed C structure for a big-endian + machine: + + + struct select_ccb { + uint32_t header; + uint32_t control; + uint64_t completion; + uint64_t primary_input; + uint64_t data_access_control; + uint64_t secondary_input; + uint64_t reserved; + uint64_t output; + uint64_t table; + }; + + + The exact field offsets, sizes, and composition are as follows: + + Offset Size Field Description + 0 4 CCB header (Table 36.1, “CCB Header Format”) + 4 4 Command control + Bits Field Description + [31:28] Primary Input Format (see Section 36.2.1.1.1, “Primary Input + Format”) + [27:23] Primary Input Element Size (see Section 36.2.1.1.2, “Primary + Input Element Size”) + [22:20] Primary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [19] Secondary Input Format (see Section 36.2.1.1.3, “Secondary + Input Format”) + [18:16] Secondary Input Starting Offset (see Section 36.2.1.1.5, “Input + Element Offsets”) + [15:14] Secondary Input Element Size (see Section 36.2.1.1.4, + “Secondary Input Element Size” + + + 524 + Coprocessor services + + + Offset Size Field Description + Bits Field Description + [13:10] Output Format (see Section 36.2.1.1.6, “Output Format”) + [9] Padding Direction selector: A value of 1 causes padding bytes + to be added to the left side of output elements. A value of 0 + causes padding bytes to be added to the right side of output + elements. + [8:0] Reserved + 8 8 Completion (same fields as Section 36.2.1.2, “Extract command” + 16 8 Primary Input (same fields as Section 36.2.1.2, “Extract command” + 24 8 Data Access Control (same fields as Section 36.2.1.2, “Extract command”) + 32 8 Secondary Bit Vector Input. Same fields as Primary Input. + 40 8 Reserved + 48 8 Output (same fields as Primary Input) + 56 8 Symbol Table (if used by Primary Input). Same fields as Section 36.2.1.2, + “Extract command” + +36.2.1.6. No-op and Sync commands + The no-op (no operation) command is a CCB which has no processing effect. The CCB, when processed + by the virtual machine, simply updates the completion area with its execution status. The CCB may have + the serial-conditional flags set in order to restrict when it executes. + + The sync command is a variant of the no-op command which with restricted execution timing. A sync + command CCB will only execute when all previous commands submitted in the same request have + completed. This is stronger than the conditional flag sequencing, which is only dependent on a single + previous serial CCB. While the relative ordering is guaranteed, virtual machine implementations with + shared hardware resources may cause the sync command to wait for longer than the minimum required + time. + + The return value of the CCB completion area is invalid for these CCBs. The “number of elements + processed” field is also invalid for these CCBs. + + These commands are 64-byte “short format” CCBs. + + The no-op CCB command format can be specified by the following packed C structure for a big-endian + machine: + + + struct nop_ccb { + uint32_t header; + uint32_t control; + uint64_t completion; + uint64_t reserved[6]; + }; + + + The exact field offsets, sizes, and composition are as follows: + + Offset Size Field Description + 0 4 CCB header (Table 36.1, “CCB Header Format”) + + + 525 + Coprocessor services + + + Offset Size Field Description + 4 4 Command control + Bits Field Description + [31] If set, this CCB functions as a Sync command. If clear, this + CCB functions as a No-op command. + [30:0] Reserved + 8 8 Completion (same fields as Section 36.2.1.2, “Extract command” + 16 46 Reserved + +36.2.2. CCB Completion Area + All CCB commands use a common 128-byte Completion Area format, which can be specified by the + following packed C structure for a big-endian machine: + + + struct completion_area { + uint8_t status_flag; + uint8_t error_note; + uint8_t rsvd0[2]; + uint32_t error_values; + uint32_t output_size; + uint32_t rsvd1; + uint64_t run_time; + uint64_t run_stats; + uint32_t elements; + uint8_t rsvd2[20]; + uint64_t return_value; + uint64_t extra_return_value[8]; + }; + + + The Completion Area must be a 128-byte aligned memory location. The exact layout can be described + using byte offsets and sizes relative to the memory base: + + Offset Size Field Description + 0 1 CCB execution status + 0x0 Command not yet completed + 0x1 Command ran and succeeded + 0x2 Command ran and failed (partial results may be been + produced) + 0x3 Command ran and was killed (partial execution may + have occurred) + 0x4 Command was not run + 0x5-0xF Reserved + 1 1 Error reason code + 0x0 Reserved + 0x1 Buffer overflow + + + 526 + Coprocessor services + + +Offset Size Field Description + 0x2 CCB decoding error + 0x3 Page overflow + 0x4-0x6 Reserved + 0x7 Command was killed + 0x8 Command execution timeout + 0x9 ADI miscompare error + 0xA Data format error + 0xB-0xD Reserved + 0xE Unexpected hardware error (Do not retry) + 0xF Unexpected hardware error (Retry is ok) + 0x10-0x7F Reserved + 0x80 Partial Symbol Warning + 0x81-0xFF Reserved +2 2 Reserved +4 4 If a partial symbol warning was generated, this field contains the number + of remaining bits which were not decoded. +8 4 Number of bytes of output produced +12 4 Reserved +16 8 Runtime of command (unspecified time units) +24 8 Reserved +32 4 Number of elements processed +36 20 Reserved +56 8 Return value +64 64 Extended return value + +The CCB completion area should be treated as read-only by guest software. The CCB execution status +byte will be cleared by the Hypervisor to reflect the pending execution status when the CCB is submitted +successfully. All other fields are considered invalid upon CCB submission until the CCB execution status +byte becomes non-zero. + +CCBs which complete with status 0x2 or 0x3 may produce partial results and/or side effects due to partial +execution of the CCB command. Some valid data may be accessible depending on the fault type, however, +it is recommended that guest software treat the destination buffer as being in an unknown state. If a CCB +completes with a status byte of 0x2, the error reason code byte can be read to determine what corrective +action should be taken. + +A buffer overflow indicates that the results of the operation exceeded the size of the output buffer indicated +in the CCB. The operation can be retried by resubmitting the CCB with a larger output buffer. + +A CCB decoding error indicates that the CCB contained some invalid field values. It may be also be +triggered if the CCB output is directed at a non-existent secondary input and the pipelining hint is followed. + +A page overflow error indicates that the operation required accessing a memory location beyond the page +size associated with a given address. No data will have been read or written past the page boundary, but +partial results may have been written to the destination buffer. The CCB can be resubmitted with a larger +page size memory allocation to complete the operation. + + + 527 + Coprocessor services + + + In the case of pipelined CCBs, a page overflow error will be triggered if the output from the pipeline source + CCB ends before the input of the pipeline target CCB. Page boundaries are ignored when the pipeline + hint is followed. + + Command kill indicates that the CCB execution was halted or prevented by use of the ccb_kill API call. + + Command timeout indicates that the CCB execution began, but did not complete within a pre-determined + limit set by the virtual machine. The command may have produced some or no output. The CCB may be + resubmitted with no alterations. + + ADI miscompare indicates that the memory buffer version specified in the CCB did not match the value + in memory when accessed by the virtual machine. Guest software should not attempt to resubmit the CCB + without determining the cause of the version mismatch. + + A data format error indicates that the input data stream did not follow the specified data input formatting + selected in the CCB. + + Some CCBs which encounter hardware errors may be resubmitted without change. Persistent hardware + errors may result in multiple failures until RAS software can identify and isolate the faulty component. + + The output size field indicates the number of bytes of valid output in the destination buffer. This field is + not valid for all possible CCB commands. + + The runtime field indicates the execution time of the CCB command once it leaves the internal virtual + machine queue. The time units are fixed, but unspecified, allowing only relative timing comparisons + by guest software. The time units may also vary by hardware platform, and should not be construed to + represent any absolute time value. + + Some data query commands process data in units of elements. If applicable to the command, the number of + elements processed is indicated in the listed field. This field is not valid for all possible CCB commands. + + The return value and extended return value fields are output locations for commands which do not use + a destination output buffer, or have secondary return results. The field is not valid for all possible CCB + commands. + +36.3. Hypervisor API Functions +36.3.1. ccb_submit + trap# FAST_TRAP + function# CCB_SUBMIT + arg0 address + arg1 length + arg2 flags + arg3 reserved + ret0 status + ret1 length + ret2 status data + ret3 reserved + + Submit one or more coprocessor control blocks (CCBs) for evaluation and processing by the virtual + machine. The CCBs are passed in a linear array indicated by address. length indicates the size of + the array in bytes. + + + 528 + Coprocessor services + + +The address should be aligned to the size indicated by length, rounded up to the nearest power of +two. Virtual machines implementations may reject submissions which do not adhere to that alignment. +length must be a multiple of 64 bytes. If length is zero, the maximum supported array length will be +returned as length in ret1. In all other cases, the length value in ret1 will reflect the number of bytes +successfully consumed from the input CCB array. + + Implementation note + Virtual machines should never reject submissions based on the alignment of address if the + entire array is contained within a single memory page of the smallest page size supported by the + virtual machine. + +A guest may choose to submit addresses used in this API function, including the CCB array address, +as either a real or virtual addresses, with the type of each address indicated in flags. Virtual addresses +must be present in either the TLB or an active TSB to be processed. The translation context for virtual +addresses is determined by a combination of CCB contents and the flags argument. + +The flags argument is divided into multiple fields defined as follows: + + +Bits Field Description +[63:16] Reserved +[15] Disable ADI for VA reads (in API 2.0) + Reserved (in API 1.0) +[14] Virtual addresses within CCBs are translated in privileged context +[13:12] Alternate translation context for virtual addresses within CCBs: + 0b'00 CCBs requesting alternate context are rejected + 0b'01 Reserved + 0b'10 CCBs requesting alternate context use secondary context + 0b'11 CCBs requesting alternate context use nucleus context +[11:9] Reserved +[8] Queue info flag +[7] All-or-nothing flag +[6] If address is a virtual address, treat its translation context as privileged +[5:4] Address type of address: + 0b'00 Real address + 0b'01 Virtual address in primary context + 0b'10 Virtual address in secondary context + 0b'11 Virtual address in nucleus context +[3:2] Reserved +[1:0] CCB command type: + 0b'00 Reserved + 0b'01 Reserved + 0b'10 Query command + 0b'11 Reserved + + + + 529 + Coprocessor services + + + The CCB submission type and address type for the CCB array must be provided in the flags argument. + All other fields are optional values which change the default behavior of the CCB processing. + + When set to one, the "Disable ADI for VA reads" bit will turn off ADI checking when using a virtual + address to load data. ADI checking will still be done when loading real-addressed memory. This bit is only + available when using major version 2 of the coprocessor API group; at major version 1 it is reserved. For + more information about using ADI and DAX, see Section 36.2.1.1.7, “Application Data Integrity (ADI)”. + + By default, all virtual addresses are treated as user addresses. If the virtual address translations are + privileged, they must be marked as such in the appropriate flags field. The virtual addresses used within + the submitted CCBs must all be translated with the same privilege level. + + By default, all virtual addresses used within the submitted CCBs are translated using the primary context + active at the time of the submission. The address type field within a CCB allows each address to request + translation in an alternate address context. The address context used when the alternate address context is + requested is selected in the flags argument. + + The all-or-nothing flag specifies whether the virtual machine should allow partial submissions of the + input CCB array. When using CCBs with serial-conditional flags, it is strongly recommended to use + the all-or-nothing flag to avoid broken conditional chains. Using long CCB chains on a machine under + high coprocessor load may make this impractical, however, and require submitting without the flag. + When submitting serial-conditional CCBs without the all-or-nothing flag, guest software must manually + implement the serial-conditional behavior at any point where the chain was not submitted in a single API + call, and resubmission of the remaining CCBs should clear any conditional flag that might be set in the + first remaining CCB. Failure to do so will produce indeterminate CCB execution status and ordering. + + When the all-or-nothing flag is not specified, callers should check the value of length in ret1 to determine + how many CCBs from the array were successfully submitted. Any remaining CCBs can be resubmitted + without modifications. + + The value of length in ret1 is also valid when the API call returns an error, and callers should always + check its value to determine which CCBs in the array were already processed. This will additionally + identify which CCB encountered the processing error, and was not submitted successfully. + + If the queue info flag is used during submission, and at least one CCB was successfully submitted, the + length value in ret1 will be a multi-field value defined as follows: + Bits Field Description + [63:48] DAX unit instance identifier + [47:32] DAX queue instance identifier + [31:16] Reserved + [15:0] Number of CCB bytes successfully submitted + + The value of status data depends on the status value. See error status code descriptions for details. + The value is undefined for status values that do not specifically list a value for the status data. + + The API has a reserved input and output register which will be used in subsequent minor versions of this + API function. Guest software implementations should treat that register as voltile across the function call + in order to maintain forward compatibility. + +36.3.1.1. Errors + EOK One or more CCBs have been accepted and enqueued in the virtual machine + and no errors were been encountered during submission. Some submitted + CCBs may not have been enqueued due to internal virtual machine limitations, + and may be resubmitted without changes. + + + 530 + Coprocessor services + + +EWOULDBLOCK An internal resource conflict within the virtual machine has prevented it from + being able to complete the CCB submissions sufficiently quickly, requiring + it to abandon processing before it was complete. Some CCBs may have been + successfully enqueued prior to the block, and all remaining CCBs may be + resubmitted without changes. +EBADALIGN CCB array is not on a 64-byte boundary, or the array length is not a multiple + of 64 bytes. +ENORADDR A real address used either for the CCB array, or within one of the submitted + CCBs, is not valid for the guest. Some CCBs may have been enqueued prior + to the error being detected. +ENOMAP A virtual address used either for the CCB array, or within one of the submitted + CCBs, could not be translated by the virtual machine using either the TLB + or TSB contents. The submission may be retried after adding the required + mapping, or by converting the virtual address into a real address. Due to the + shared nature of address translation resources, there is no theoretical limit on + the number of times the translation may fail, and it is recommended all guests + implement some real address based backup. The virtual address which failed + translation is returned as status data in ret2. Some CCBs may have been + enqueued prior to the error being detected. +EINVAL The virtual machine detected an invalid CCB during submission, or invalid + input arguments, such as bad flag values. Note that not all invalid CCB values + will be detected during submission, and some may be reported as errors in the + completion area instead. Some CCBs may have been enqueued prior to the + error being detected. This error may be returned if the CCB version is invalid. +ETOOMANY The request was submitted with the all-or-nothing flag set, and the array size is + greater than the virtual machine can support in a single request. The maximum + supported size for the current virtual machine can be queried by submitting a + request with a zero length array, as described above. +ENOACCESS The guest does not have permission to submit CCBs, or an address used in a + CCBs lacks sufficient permissions to perform the required operation (no write + permission on the destination buffer address, for example). A virtual address + which fails permission checking is returned as status data in ret2. Some + CCBs may have been enqueued prior to the error being detected. +EUNAVAILABLE The requested CCB operation could not be performed at this time. The + restricted operation availability may apply only to the first unsuccessfully + submitted CCB, or may apply to a larger scope. The status should not be + interpreted as permanent, and the guest should attempt to submit CCBs in + the future which had previously been unable to be performed. The status + data provides additional information about scope of the restricted availability + as follows: + Value Description + 0 Processing for the exact CCB instance submitted was unavailable, + and it is recommended the guest emulate the operation. The + guest should continue to submit all other CCBs, and assume no + restrictions beyond this exact CCB instance. + 1 Processing is unavailable for all CCBs using the requested opcode, + and it is recommended the guest emulate the operation. The + guest should continue to submit all other CCBs that use different + opcodes, but can expect continued rejections of CCBs using the + same opcode in the near future. + + + 531 + Coprocessor services + + + Value Description + 2 Processing is unavailable for all CCBs using the requested CCB + version, and it is recommended the guest emulate the operation. + The guest should continue to submit all other CCBs that use + different CCB versions, but can expect continued rejections of + CCBs using the same CCB version in the near future. + 3 Processing is unavailable for all CCBs on the submitting vcpu, + and it is recommended the guest emulate the operation or resubmit + the CCB on a different vcpu. The guest should continue to submit + CCBs on all other vcpus but can expect continued rejections of all + CCBs on this vcpu in the near future. + 4 Processing is unavailable for all CCBs, and it is recommended + the guest emulate the operation. The guest should expect all CCB + submissions to be similarly rejected in the near future. + + +36.3.2. ccb_info + + trap# FAST_TRAP + function# CCB_INFO + arg0 address + ret0 status + ret1 CCB state + ret2 position + ret3 dax + ret4 queue + + Requests status information on a previously submitted CCB. The previously submitted CCB is identified + by the 64-byte aligned real address of the CCBs completion area. + + A CCB can be in one of 4 states: + + + State Value Description + COMPLETED 0 The CCB has been fetched and executed, and is no longer active in + the virtual machine. + ENQUEUED 1 The requested CCB is current in a queue awaiting execution. + INPROGRESS 2 The CCB has been fetched and is currently being executed. It may still + be possible to stop the execution using the ccb_kill hypercall. + NOTFOUND 3 The CCB could not be located in the virtual machine, and does not + appear to have been executed. This may occur if the CCB was lost + due to a hardware error, or the CCB may not have been successfully + submitted to the virtual machine in the first place. + + Implementation note + Some platforms may not be able to report CCBs that are currently being processed, and therefore + guest software should invoke the ccb_kill hypercall prior to assuming the request CCB will never + be executed because it was in the NOTFOUND state. + + + 532 + Coprocessor services + + + The position return value is only valid when the state is ENQUEUED. The value returned is the number + of other CCBs ahead of the requested CCB, to provide a relative estimate of when the CCB may execute. + + The dax return value is only valid when the state is ENQUEUED. The value returned is the DAX unit + instance identifier for the DAX unit processing the queue where the requested CCB is located. The value + matches the value that would have been, or was, returned by ccb_submit using the queue info flag. + + The queue return value is only valid when the state is ENQUEUED. The value returned is the DAX + queue instance identifier for the DAX unit processing the queue where the requested CCB is located. The + value matches the value that would have been, or was, returned by ccb_submit using the queue info flag. + +36.3.2.1. Errors + + EOK The request was processed and the CCB state is valid. + EBADALIGN address is not on a 64-byte aligned. + ENORADDR The real address provided for address is not valid. + EINVAL The CCB completion area contents are not valid. + EWOULDBLOCK Internal resource constraints prevented the CCB state from being queried at this + time. The guest should retry the request. + ENOACCESS The guest does not have permission to access the coprocessor virtual device + functionality. + +36.3.3. ccb_kill + + trap# FAST_TRAP + function# CCB_KILL + arg0 address + ret0 status + ret1 result + + Request to stop execution of a previously submitted CCB. The previously submitted CCB is identified by + the 64-byte aligned real address of the CCBs completion area. + + The kill attempt can produce one of several values in the result return value, reflecting the CCB state + and actions taken by the Hypervisor: + + Result Value Description + COMPLETED 0 The CCB has been fetched and executed, and is no longer active in + the virtual machine. It could not be killed and no action was taken. + DEQUEUED 1 The requested CCB was still enqueued when the kill request was + submitted, and has been removed from the queue. Since the CCB + never began execution, no memory modifications were produced by + it, and the completion area will never be updated. The same CCB may + be submitted again, if desired, with no modifications required. + KILLED 2 The CCB had been fetched and was being executed when the kill + request was submitted. The CCB execution was stopped, and the CCB + is no longer active in the virtual machine. The CCB completion area + will reflect the killed status, with the subsequent implications that + partial results may have been produced. Partial results may include full + + + 533 + Coprocessor services + + + Result Value Description + command execution if the command was stopped just prior to writing + to the completion area. + NOTFOUND 3 The CCB could not be located in the virtual machine, and does not + appear to have been executed. This may occur if the CCB was lost + due to a hardware error, or the CCB may not have been successfully + submitted to the virtual machine in the first place. CCBs in the state + are guaranteed to never execute in the future unless resubmitted. + +36.3.3.1. Interactions with Pipelined CCBs + + If the pipeline target CCB is killed but the pipeline source CCB was skipped, the completion area of the + target CCB may contain status (4,0) "Command was skipped" instead of (3,7) "Command was killed". + + If the pipeline source CCB is killed, the pipeline target CCB's completion status may read (1,0) "Success". + This does not mean the target CCB was processed; since the source CCB was killed, there was no + meaningful output on which the target CCB could operate. + +36.3.3.2. Errors + + EOK The request was processed and the result is valid. + EBADALIGN address is not on a 64-byte aligned. + ENORADDR The real address provided for address is not valid. + EINVAL The CCB completion area contents are not valid. + EWOULDBLOCK Internal resource constraints prevented the CCB from being killed at this time. + The guest should retry the request. + ENOACCESS The guest does not have permission to access the coprocessor virtual device + functionality. + +36.3.4. dax_info + trap# FAST_TRAP + function# DAX_INFO + ret0 status + ret1 Number of enabled DAX units + ret2 Number of disabled DAX units + + Returns the number of DAX units that are enabled for the calling guest to submit CCBs. The number of + DAX units that are disabled for the calling guest are also returned. A disabled DAX unit would have been + available for CCB submission to the calling guest had it not been offlined. + +36.3.4.1. Errors + + EOK The request was processed and the number of enabled/disabled DAX units + are valid. + + + + + 534 + diff --git a/Documentation/arch/sparc/oradax/oracle-dax.rst b/Documentation/arch/sparc/oradax/oracle-dax.rst new file mode 100644 index 000000000000..d1e14d572918 --- /dev/null +++ b/Documentation/arch/sparc/oradax/oracle-dax.rst @@ -0,0 +1,445 @@ +======================================= +Oracle Data Analytics Accelerator (DAX) +======================================= + +DAX is a coprocessor which resides on the SPARC M7 (DAX1) and M8 +(DAX2) processor chips, and has direct access to the CPU's L3 caches +as well as physical memory. It can perform several operations on data +streams with various input and output formats. A driver provides a +transport mechanism and has limited knowledge of the various opcodes +and data formats. A user space library provides high level services +and translates these into low level commands which are then passed +into the driver and subsequently the Hypervisor and the coprocessor. +The library is the recommended way for applications to use the +coprocessor, and the driver interface is not intended for general use. +This document describes the general flow of the driver, its +structures, and its programmatic interface. It also provides example +code sufficient to write user or kernel applications that use DAX +functionality. + +The user library is open source and available at: + + https://oss.oracle.com/git/gitweb.cgi?p=libdax.git + +The Hypervisor interface to the coprocessor is described in detail in +the accompanying document, dax-hv-api.txt, which is a plain text +excerpt of the (Oracle internal) "UltraSPARC Virtual Machine +Specification" version 3.0.20+15, dated 2017-09-25. + + +High Level Overview +=================== + +A coprocessor request is described by a Command Control Block +(CCB). The CCB contains an opcode and various parameters. The opcode +specifies what operation is to be done, and the parameters specify +options, flags, sizes, and addresses. The CCB (or an array of CCBs) +is passed to the Hypervisor, which handles queueing and scheduling of +requests to the available coprocessor execution units. A status code +returned indicates if the request was submitted successfully or if +there was an error. One of the addresses given in each CCB is a +pointer to a "completion area", which is a 128 byte memory block that +is written by the coprocessor to provide execution status. No +interrupt is generated upon completion; the completion area must be +polled by software to find out when a transaction has finished, but +the M7 and later processors provide a mechanism to pause the virtual +processor until the completion status has been updated by the +coprocessor. This is done using the monitored load and mwait +instructions, which are described in more detail later. The DAX +coprocessor was designed so that after a request is submitted, the +kernel is no longer involved in the processing of it. The polling is +done at the user level, which results in almost zero latency between +completion of a request and resumption of execution of the requesting +thread. + + +Addressing Memory +================= + +The kernel does not have access to physical memory in the Sun4v +architecture, as there is an additional level of memory virtualization +present. This intermediate level is called "real" memory, and the +kernel treats this as if it were physical. The Hypervisor handles the +translations between real memory and physical so that each logical +domain (LDOM) can have a partition of physical memory that is isolated +from that of other LDOMs. When the kernel sets up a virtual mapping, +it specifies a virtual address and the real address to which it should +be mapped. + +The DAX coprocessor can only operate on physical memory, so before a +request can be fed to the coprocessor, all the addresses in a CCB must +be converted into physical addresses. The kernel cannot do this since +it has no visibility into physical addresses. So a CCB may contain +either the virtual or real addresses of the buffers or a combination +of them. An "address type" field is available for each address that +may be given in the CCB. In all cases, the Hypervisor will translate +all the addresses to physical before dispatching to hardware. Address +translations are performed using the context of the process initiating +the request. + + +The Driver API +============== + +An application makes requests to the driver via the write() system +call, and gets results (if any) via read(). The completion areas are +made accessible via mmap(), and are read-only for the application. + +The request may either be an immediate command or an array of CCBs to +be submitted to the hardware. + +Each open instance of the device is exclusive to the thread that +opened it, and must be used by that thread for all subsequent +operations. The driver open function creates a new context for the +thread and initializes it for use. This context contains pointers and +values used internally by the driver to keep track of submitted +requests. The completion area buffer is also allocated, and this is +large enough to contain the completion areas for many concurrent +requests. When the device is closed, any outstanding transactions are +flushed and the context is cleaned up. + +On a DAX1 system (M7), the device will be called "oradax1", while on a +DAX2 system (M8) it will be "oradax2". If an application requires one +or the other, it should simply attempt to open the appropriate +device. Only one of the devices will exist on any given system, so the +name can be used to determine what the platform supports. + +The immediate commands are CCB_DEQUEUE, CCB_KILL, and CCB_INFO. For +all of these, success is indicated by a return value from write() +equal to the number of bytes given in the call. Otherwise -1 is +returned and errno is set. + +CCB_DEQUEUE +----------- + +Tells the driver to clean up resources associated with past +requests. Since no interrupt is generated upon the completion of a +request, the driver must be told when it may reclaim resources. No +further status information is returned, so the user should not +subsequently call read(). + +CCB_KILL +-------- + +Kills a CCB during execution. The CCB is guaranteed to not continue +executing once this call returns successfully. On success, read() must +be called to retrieve the result of the action. + +CCB_INFO +-------- + +Retrieves information about a currently executing CCB. Note that some +Hypervisors might return 'notfound' when the CCB is in 'inprogress' +state. To ensure a CCB in the 'notfound' state will never be executed, +CCB_KILL must be invoked on that CCB. Upon success, read() must be +called to retrieve the details of the action. + +Submission of an array of CCBs for execution +--------------------------------------------- + +A write() whose length is a multiple of the CCB size is treated as a +submit operation. The file offset is treated as the index of the +completion area to use, and may be set via lseek() or using the +pwrite() system call. If -1 is returned then errno is set to indicate +the error. Otherwise, the return value is the length of the array that +was actually accepted by the coprocessor. If the accepted length is +equal to the requested length, then the submission was completely +successful and there is no further status needed; hence, the user +should not subsequently call read(). Partial acceptance of the CCB +array is indicated by a return value less than the requested length, +and read() must be called to retrieve further status information. The +status will reflect the error caused by the first CCB that was not +accepted, and status_data will provide additional data in some cases. + +MMAP +---- + +The mmap() function provides access to the completion area allocated +in the driver. Note that the completion area is not writeable by the +user process, and the mmap call must not specify PROT_WRITE. + + +Completion of a Request +======================= + +The first byte in each completion area is the command status which is +updated by the coprocessor hardware. Software may take advantage of +new M7/M8 processor capabilities to efficiently poll this status byte. +First, a "monitored load" is achieved via a Load from Alternate Space +(ldxa, lduba, etc.) with ASI 0x84 (ASI_MONITOR_PRIMARY). Second, a +"monitored wait" is achieved via the mwait instruction (a write to +%asr28). This instruction is like pause in that it suspends execution +of the virtual processor for the given number of nanoseconds, but in +addition will terminate early when one of several events occur. If the +block of data containing the monitored location is modified, then the +mwait terminates. This causes software to resume execution immediately +(without a context switch or kernel to user transition) after a +transaction completes. Thus the latency between transaction completion +and resumption of execution may be just a few nanoseconds. + + +Application Life Cycle of a DAX Submission +========================================== + + - open dax device + - call mmap() to get the completion area address + - allocate a CCB and fill in the opcode, flags, parameters, addresses, etc. + - submit CCB via write() or pwrite() + - go into a loop executing monitored load + monitored wait and + terminate when the command status indicates the request is complete + (CCB_KILL or CCB_INFO may be used any time as necessary) + - perform a CCB_DEQUEUE + - call munmap() for completion area + - close the dax device + + +Memory Constraints +================== + +The DAX hardware operates only on physical addresses. Therefore, it is +not aware of virtual memory mappings and the discontiguities that may +exist in the physical memory that a virtual buffer maps to. There is +no I/O TLB or any scatter/gather mechanism. All buffers, whether input +or output, must reside in a physically contiguous region of memory. + +The Hypervisor translates all addresses within a CCB to physical +before handing off the CCB to DAX. The Hypervisor determines the +virtual page size for each virtual address given, and uses this to +program a size limit for each address. This prevents the coprocessor +from reading or writing beyond the bound of the virtual page, even +though it is accessing physical memory directly. A simpler way of +saying this is that a DAX operation will never "cross" a virtual page +boundary. If an 8k virtual page is used, then the data is strictly +limited to 8k. If a user's buffer is larger than 8k, then a larger +page size must be used, or the transaction size will be truncated to +8k. + +Huge pages. A user may allocate huge pages using standard interfaces. +Memory buffers residing on huge pages may be used to achieve much +larger DAX transaction sizes, but the rules must still be followed, +and no transaction will cross a page boundary, even a huge page. A +major caveat is that Linux on Sparc presents 8Mb as one of the huge +page sizes. Sparc does not actually provide a 8Mb hardware page size, +and this size is synthesized by pasting together two 4Mb pages. The +reasons for this are historical, and it creates an issue because only +half of this 8Mb page can actually be used for any given buffer in a +DAX request, and it must be either the first half or the second half; +it cannot be a 4Mb chunk in the middle, since that crosses a +(hardware) page boundary. Note that this entire issue may be hidden by +higher level libraries. + + +CCB Structure +------------- +A CCB is an array of 8 64-bit words. Several of these words provide +command opcodes, parameters, flags, etc., and the rest are addresses +for the completion area, output buffer, and various inputs:: + + struct ccb { + u64 control; + u64 completion; + u64 input0; + u64 access; + u64 input1; + u64 op_data; + u64 output; + u64 table; + }; + +See libdax/common/sys/dax1/dax1_ccb.h for a detailed description of +each of these fields, and see dax-hv-api.txt for a complete description +of the Hypervisor API available to the guest OS (ie, Linux kernel). + +The first word (control) is examined by the driver for the following: + - CCB version, which must be consistent with hardware version + - Opcode, which must be one of the documented allowable commands + - Address types, which must be set to "virtual" for all the addresses + given by the user, thereby ensuring that the application can + only access memory that it owns + + +Example Code +============ + +The DAX is accessible to both user and kernel code. The kernel code +can make hypercalls directly while the user code must use wrappers +provided by the driver. The setup of the CCB is nearly identical for +both; the only difference is in preparation of the completion area. An +example of user code is given now, with kernel code afterwards. + +In order to program using the driver API, the file +arch/sparc/include/uapi/asm/oradax.h must be included. + +First, the proper device must be opened. For M7 it will be +/dev/oradax1 and for M8 it will be /dev/oradax2. The simplest +procedure is to attempt to open both, as only one will succeed:: + + fd = open("/dev/oradax1", O_RDWR); + if (fd < 0) + fd = open("/dev/oradax2", O_RDWR); + if (fd < 0) + /* No DAX found */ + +Next, the completion area must be mapped:: + + completion_area = mmap(NULL, DAX_MMAP_LEN, PROT_READ, MAP_SHARED, fd, 0); + +All input and output buffers must be fully contained in one hardware +page, since as explained above, the DAX is strictly constrained by +virtual page boundaries. In addition, the output buffer must be +64-byte aligned and its size must be a multiple of 64 bytes because +the coprocessor writes in units of cache lines. + +This example demonstrates the DAX Scan command, which takes as input a +vector and a match value, and produces a bitmap as the output. For +each input element that matches the value, the corresponding bit is +set in the output. + +In this example, the input vector consists of a series of single bits, +and the match value is 0. So each 0 bit in the input will produce a 1 +in the output, and vice versa, which produces an output bitmap which +is the input bitmap inverted. + +For details of all the parameters and bits used in this CCB, please +refer to section 36.2.1.3 of the DAX Hypervisor API document, which +describes the Scan command in detail:: + + ccb->control = /* Table 36.1, CCB Header Format */ + (2L << 48) /* command = Scan Value */ + | (3L << 40) /* output address type = primary virtual */ + | (3L << 34) /* primary input address type = primary virtual */ + /* Section 36.2.1, Query CCB Command Formats */ + | (1 << 28) /* 36.2.1.1.1 primary input format = fixed width bit packed */ + | (0 << 23) /* 36.2.1.1.2 primary input element size = 0 (1 bit) */ + | (8 << 10) /* 36.2.1.1.6 output format = bit vector */ + | (0 << 5) /* 36.2.1.3 First scan criteria size = 0 (1 byte) */ + | (31 << 0); /* 36.2.1.3 Disable second scan criteria */ + + ccb->completion = 0; /* Completion area address, to be filled in by driver */ + + ccb->input0 = (unsigned long) input; /* primary input address */ + + ccb->access = /* Section 36.2.1.2, Data Access Control */ + (2 << 24) /* Primary input length format = bits */ + | (nbits - 1); /* number of bits in primary input stream, minus 1 */ + + ccb->input1 = 0; /* secondary input address, unused */ + + ccb->op_data = 0; /* scan criteria (value to be matched) */ + + ccb->output = (unsigned long) output; /* output address */ + + ccb->table = 0; /* table address, unused */ + +The CCB submission is a write() or pwrite() system call to the +driver. If the call fails, then a read() must be used to retrieve the +status:: + + if (pwrite(fd, ccb, 64, 0) != 64) { + struct ccb_exec_result status; + read(fd, &status, sizeof(status)); + /* bail out */ + } + +After a successful submission of the CCB, the completion area may be +polled to determine when the DAX is finished. Detailed information on +the contents of the completion area can be found in section 36.2.2 of +the DAX HV API document:: + + while (1) { + /* Monitored Load */ + __asm__ __volatile__("lduba [%1] 0x84, %0\n" + : "=r" (status) + : "r" (completion_area)); + + if (status) /* 0 indicates command in progress */ + break; + + /* MWAIT */ + __asm__ __volatile__("wr %%g0, 1000, %%asr28\n" ::); /* 1000 ns */ + } + +A completion area status of 1 indicates successful completion of the +CCB and validity of the output bitmap, which may be used immediately. +All other non-zero values indicate error conditions which are +described in section 36.2.2:: + + if (completion_area[0] != 1) { /* section 36.2.2, 1 = command ran and succeeded */ + /* completion_area[0] contains the completion status */ + /* completion_area[1] contains an error code, see 36.2.2 */ + } + +After the completion area has been processed, the driver must be +notified that it can release any resources associated with the +request. This is done via the dequeue operation:: + + struct dax_command cmd; + cmd.command = CCB_DEQUEUE; + if (write(fd, &cmd, sizeof(cmd)) != sizeof(cmd)) { + /* bail out */ + } + +Finally, normal program cleanup should be done, i.e., unmapping +completion area, closing the dax device, freeing memory etc. + +Kernel example +-------------- + +The only difference in using the DAX in kernel code is the treatment +of the completion area. Unlike user applications which mmap the +completion area allocated by the driver, kernel code must allocate its +own memory to use for the completion area, and this address and its +type must be given in the CCB:: + + ccb->control |= /* Table 36.1, CCB Header Format */ + (3L << 32); /* completion area address type = primary virtual */ + + ccb->completion = (unsigned long) completion_area; /* Completion area address */ + +The dax submit hypercall is made directly. The flags used in the +ccb_submit call are documented in the DAX HV API in section 36.3.1/ + +:: + + #include <asm/hypervisor.h> + + hv_rv = sun4v_ccb_submit((unsigned long)ccb, 64, + HV_CCB_QUERY_CMD | + HV_CCB_ARG0_PRIVILEGED | HV_CCB_ARG0_TYPE_PRIMARY | + HV_CCB_VA_PRIVILEGED, + 0, &bytes_accepted, &status_data); + + if (hv_rv != HV_EOK) { + /* hv_rv is an error code, status_data contains */ + /* potential additional status, see 36.3.1.1 */ + } + +After the submission, the completion area polling code is identical to +that in user land:: + + while (1) { + /* Monitored Load */ + __asm__ __volatile__("lduba [%1] 0x84, %0\n" + : "=r" (status) + : "r" (completion_area)); + + if (status) /* 0 indicates command in progress */ + break; + + /* MWAIT */ + __asm__ __volatile__("wr %%g0, 1000, %%asr28\n" ::); /* 1000 ns */ + } + + if (completion_area[0] != 1) { /* section 36.2.2, 1 = command ran and succeeded */ + /* completion_area[0] contains the completion status */ + /* completion_area[1] contains an error code, see 36.2.2 */ + } + +The output bitmap is ready for consumption immediately after the +completion status indicates success. + +Excer[t from UltraSPARC Virtual Machine Specification +===================================================== + + .. include:: dax-hv-api.txt + :literal: |