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2020-06-01Merge tag 'docs-5.8' of git://git.lwn.net/linuxLinus Torvalds2-3/+3
Pull documentation updates from Jonathan Corbet: "A fair amount of stuff this time around, dominated by yet another massive set from Mauro toward the completion of the RST conversion. I *really* hope we are getting close to the end of this. Meanwhile, those patches reach pretty far afield to update document references around the tree; there should be no actual code changes there. There will be, alas, more of the usual trivial merge conflicts. Beyond that we have more translations, improvements to the sphinx scripting, a number of additions to the sysctl documentation, and lots of fixes" * tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits) Documentation: fixes to the maintainer-entry-profile template zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst tracing: Fix events.rst section numbering docs: acpi: fix old http link and improve document format docs: filesystems: add info about efivars content Documentation: LSM: Correct the basic LSM description mailmap: change email for Ricardo Ribalda docs: sysctl/kernel: document unaligned controls Documentation: admin-guide: update bug-hunting.rst docs: sysctl/kernel: document ngroups_max nvdimm: fixes to maintainter-entry-profile Documentation/features: Correct RISC-V kprobes support entry Documentation/features: Refresh the arch support status files Revert "docs: sysctl/kernel: document ngroups_max" docs: move locking-specific documents to locking/ docs: move digsig docs to the security book docs: move the kref doc into the core-api book docs: add IRQ documentation at the core-api book docs: debugging-via-ohci1394.txt: add it to the core-api book docs: fix references for ipmi.rst file ...
2020-06-01Merge tag 'arm64-upstream' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "A sizeable pile of arm64 updates for 5.8. Summary below, but the big two features are support for Branch Target Identification and Clang's Shadow Call stack. The latter is currently arm64-only, but the high-level parts are all in core code so it could easily be adopted by other architectures pending toolchain support Branch Target Identification (BTI): - Support for ARMv8.5-BTI in both user- and kernel-space. This allows branch targets to limit the types of branch from which they can be called and additionally prevents branching to arbitrary code, although kernel support requires a very recent toolchain. - Function annotation via SYM_FUNC_START() so that assembly functions are wrapped with the relevant "landing pad" instructions. - BPF and vDSO updates to use the new instructions. - Addition of a new HWCAP and exposure of BTI capability to userspace via ID register emulation, along with ELF loader support for the BTI feature in .note.gnu.property. - Non-critical fixes to CFI unwind annotations in the sigreturn trampoline. Shadow Call Stack (SCS): - Support for Clang's Shadow Call Stack feature, which reserves platform register x18 to point at a separate stack for each task that holds only return addresses. This protects function return control flow from buffer overruns on the main stack. - Save/restore of x18 across problematic boundaries (user-mode, hypervisor, EFI, suspend, etc). - Core support for SCS, should other architectures want to use it too. - SCS overflow checking on context-switch as part of the existing stack limit check if CONFIG_SCHED_STACK_END_CHECK=y. CPU feature detection: - Removed numerous "SANITY CHECK" errors when running on a system with mismatched AArch32 support at EL1. This is primarily a concern for KVM, which disabled support for 32-bit guests on such a system. - Addition of new ID registers and fields as the architecture has been extended. Perf and PMU drivers: - Minor fixes and cleanups to system PMU drivers. Hardware errata: - Unify KVM workarounds for VHE and nVHE configurations. - Sort vendor errata entries in Kconfig. Secure Monitor Call Calling Convention (SMCCC): - Update to the latest specification from Arm (v1.2). - Allow PSCI code to query the SMCCC version. Software Delegated Exception Interface (SDEI): - Unexport a bunch of unused symbols. - Minor fixes to handling of firmware data. Pointer authentication: - Add support for dumping the kernel PAC mask in vmcoreinfo so that the stack can be unwound by tools such as kdump. - Simplification of key initialisation during CPU bringup. BPF backend: - Improve immediate generation for logical and add/sub instructions. vDSO: - Minor fixes to the linker flags for consistency with other architectures and support for LLVM's unwinder. - Clean up logic to initialise and map the vDSO into userspace. ACPI: - Work around for an ambiguity in the IORT specification relating to the "num_ids" field. - Support _DMA method for all named components rather than only PCIe root complexes. - Minor other IORT-related fixes. Miscellaneous: - Initialise debug traps early for KGDB and fix KDB cacheflushing deadlock. - Minor tweaks to early boot state (documentation update, set TEXT_OFFSET to 0x0, increase alignment of PE/COFF sections). - Refactoring and cleanup" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits) KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h KVM: arm64: Check advertised Stage-2 page size capability arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() ACPI/IORT: Remove the unused __get_pci_rid() arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register arm64/cpufeature: Add remaining feature bits in ID_PFR0 register arm64/cpufeature: Introduce ID_MMFR5 CPU register arm64/cpufeature: Introduce ID_DFR1 CPU register arm64/cpufeature: Introduce ID_PFR2 CPU register arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0 arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register arm64: mm: Add asid_gen_match() helper firmware: smccc: Fix missing prototype warning for arm_smccc_version_init arm64: vdso: Fix CFI directives in sigreturn trampoline arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction ...
2020-05-28KVM: arm64: Check advertised Stage-2 page size capabilityMarc Zyngier1-3/+1
With ARMv8.5-GTG, the hardware (or more likely a hypervisor) can advertise the supported Stage-2 page sizes. Let's check this at boot time. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
2020-05-08KVM: Introduce kvm_make_all_cpus_request_except()Suravee Suthikulpanit1-3/+11
This allows making request to all other vcpus except the one specified in the parameter. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <1588771076-73790-2-git-send-email-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-01KVM: arm64: Fix 32bit PC wrap-aroundMarc Zyngier1-2/+6
In the unlikely event that a 32bit vcpu traps into the hypervisor on an instruction that is located right at the end of the 32bit range, the emulation of that instruction is going to increment PC past the 32bit range. This isn't great, as userspace can then observe this value and get a bit confused. Conversly, userspace can do things like (in the context of a 64bit guest that is capable of 32bit EL0) setting PSTATE to AArch64-EL0, set PC to a 64bit value, change PSTATE to AArch32-USR, and observe that PC hasn't been truncated. More confusion. Fix both by: - truncating PC increments for 32bit guests - sanitizing all 32bit regs every time a core reg is changed by userspace, and that PSTATE indicates a 32bit mode. Cc: stable@vger.kernel.org Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-30KVM: arm64: vgic-v4: Initialize GICv4.1 even in the absence of a virtual ITSMarc Zyngier2-2/+10
KVM now expects to be able to use HW-accelerated delivery of vSGIs as soon as the guest has enabled thm. Unfortunately, we only initialize the GICv4 context if we have a virtual ITS exposed to the guest. Fix it by always initializing the GICv4.1 context if it is available on the host. Fixes: 2291ff2f2a56 ("KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor") Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-23Merge branch 'kvm-arm64/vgic-fixes-5.7' into kvmarm-master/masterMarc Zyngier6-80/+232
2020-04-23KVM: arm64: vgic-its: Fix memory leak on the error path of vgic_add_lpi()Zenghui Yu1-2/+9
If we're going to fail out the vgic_add_lpi(), let's make sure the allocated vgic_irq memory is also freed. Though it seems that both cases are unlikely to fail. Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200414030349.625-3-yuzenghui@huawei.com
2020-04-23KVM: arm64: vgic-v3: Retire all pending LPIs on vcpu destroyZenghui Yu1-2/+8
It's likely that the vcpu fails to handle all virtual interrupts if userspace decides to destroy it, leaving the pending ones stay in the ap_list. If the un-handled one is a LPI, its vgic_irq structure will be eventually leaked because of an extra refcount increment in vgic_queue_irq_unlock(). This was detected by kmemleak on almost every guest destroy, the backtrace is as follows: unreferenced object 0xffff80725aed5500 (size 128): comm "CPU 5/KVM", pid 40711, jiffies 4298024754 (age 166366.512s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 01 a9 73 6d 80 ff ff ...........sm... c8 61 ee a9 00 20 ff ff 28 1e 55 81 6c 80 ff ff .a... ..(.U.l... backtrace: [<000000004bcaa122>] kmem_cache_alloc_trace+0x2dc/0x418 [<0000000069c7dabb>] vgic_add_lpi+0x88/0x418 [<00000000bfefd5c5>] vgic_its_cmd_handle_mapi+0x4dc/0x588 [<00000000cf993975>] vgic_its_process_commands.part.5+0x484/0x1198 [<000000004bd3f8e3>] vgic_its_process_commands+0x50/0x80 [<00000000b9a65b2b>] vgic_mmio_write_its_cwriter+0xac/0x108 [<0000000009641ebb>] dispatch_mmio_write+0xd0/0x188 [<000000008f79d288>] __kvm_io_bus_write+0x134/0x240 [<00000000882f39ac>] kvm_io_bus_write+0xe0/0x150 [<0000000078197602>] io_mem_abort+0x484/0x7b8 [<0000000060954e3c>] kvm_handle_guest_abort+0x4cc/0xa58 [<00000000e0d0cd65>] handle_exit+0x24c/0x770 [<00000000b44a7fad>] kvm_arch_vcpu_ioctl_run+0x460/0x1988 [<0000000025fb897c>] kvm_vcpu_ioctl+0x4f8/0xee0 [<000000003271e317>] do_vfs_ioctl+0x160/0xcd8 [<00000000e7f39607>] ksys_ioctl+0x98/0xd8 Fix it by retiring all pending LPIs in the ap_list on the destroy path. p.s. I can also reproduce it on a normal guest shutdown. It is because userspace still send LPIs to vcpu (through KVM_SIGNAL_MSI ioctl) while the guest is being shutdown and unable to handle it. A little strange though and haven't dig further... Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> [maz: moved the distributor deallocation down to avoid an UAF splat] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200414030349.625-2-yuzenghui@huawei.com
2020-04-23KVM: arm: vgic-v2: Only use the virtual state when userspace accesses ↵Marc Zyngier3-24/+76
pending bits There is no point in accessing the HW when writing to any of the ISPENDR/ICPENDR registers from userspace, as only the guest should be allowed to change the HW state. Introduce new userspace-specific accessors that deal solely with the virtual state. Note that the API differs from that of GICv3, where userspace exclusively uses ISPENDR to set the state. Too bad we can't reuse it. Fixes: 82e40f558de56 ("KVM: arm/arm64: vgic-v2: Handle SGI bits in GICD_I{S,C}PENDR0 as WI") Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-22KVM: arm: vgic: Only use the virtual state when userspace accesses enable bitsMarc Zyngier4-8/+64
There is no point in accessing the HW when writing to any of the ISENABLER/ICENABLER registers from userspace, as only the guest should be allowed to change the HW state. Introduce new userspace-specific accessors that deal solely with the virtual state. Reported-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-22KVM: arm: vgic: Synchronize the whole guest on GIC{D,R}_I{S,C}ACTIVER readMarc Zyngier4-44/+75
When a guest tries to read the active state of its interrupts, we currently just return whatever state we have in memory. This means that if such an interrupt lives in a List Register on another CPU, we fail to obsertve the latest active state for this interrupt. In order to remedy this, stop all the other vcpus so that they exit and we can observe the most recent value for the state. This is similar to what we are doing for the write side of the same registers, and results in new MMIO handlers for userspace (which do not need to stop the guest, as it is supposed to be stopped already). Reported-by: Julien Grall <julien@xen.org> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-20docs: fix broken references to text filesMauro Carvalho Chehab2-3/+3
Several references got broken due to txt to ReST conversion. Several of them can be automatically fixed with: scripts/documentation-file-ref-check --fix Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> # hwtracing/coresight/Kconfig Reviewed-by: Paul E. McKenney <paulmck@kernel.org> # memory-barrier.txt Acked-by: Alex Shi <alex.shi@linux.alibaba.com> # translations/zh_CN Acked-by: Federico Vaga <federico.vaga@vaga.pv.it> # translations/it_IT Acked-by: Marc Zyngier <maz@kernel.org> # kvm/arm64 Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-17KVM: arm64: PSCI: Forbid 64bit functions for 32bit guestsMarc Zyngier1-0/+24
Implementing (and even advertising) 64bit PSCI functions to 32bit guests is at least a bit odd, if not altogether violating the spec which says ("5.2.1 Register usage in arguments and return values"): "Adherence to the SMC Calling Conventions implies that any AArch32 caller of an SMC64 function will get a return code of 0xFFFFFFFF(int32). This matches the NOT_SUPPORTED error code used in PSCI" Tighten the implementation by pretending these functions are not there for 32bit guests. Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-17KVM: arm64: PSCI: Narrow input registers when using 32bit functionsMarc Zyngier1-0/+16
When a guest delibarately uses an SMC32 function number (which is allowed), we should make sure we drop the top 32bits from the input arguments, as they could legitimately be junk. Reported-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-15KVM: arm: vgic: Fix limit condition when writing to GICD_I[CS]ACTIVERMarc Zyngier1-2/+2
When deciding whether a guest has to be stopped we check whether this is a private interrupt or not. Unfortunately, there's an off-by-one bug here, and we fail to recognize a whole range of interrupts as being global (GICv2 SPIs 32-63). Fix the condition from > to be >=. Cc: stable@vger.kernel.org Fixes: abd7229626b93 ("KVM: arm/arm64: Simplify active_change_prepare and plug race") Reported-by: André Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-31KVM: Pass kvm_init()'s opaque param to additional arch funcsSean Christopherson2-6/+16
Pass @opaque to kvm_arch_hardware_setup() and kvm_arch_check_processor_compat() to allow architecture specific code to reference @opaque without having to stash it away in a temporary global variable. This will enable x86 to separate its vendor specific callback ops, which are passed via @opaque, into "init" and "runtime" ops without having to stash away the "init" ops. No functional change intended. Reviewed-by: Cornelia Huck <cohuck@redhat.com> Tested-by: Cornelia Huck <cohuck@redhat.com> #s390 Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200321202603.19355-2-sean.j.christopherson@intel.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31Merge tag 'kvmarm-5.7' of ↵Paolo Bonzini9-37/+307
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm updates for Linux 5.7 - GICv4.1 support - 32bit host removal
2020-03-26KVM: Fix out of range accesses to memslotsSean Christopherson1-0/+3
Reset the LRU slot if it becomes invalid when deleting a memslot to fix an out-of-bounds/use-after-free access when searching through memslots. Explicitly check for there being no used slots in search_memslots(), and in the caller of s390's approximation variant. Fixes: 36947254e5f9 ("KVM: Dynamically size memslot array based on number of used slots") Reported-by: Qian Cai <cai@lca.pw> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200320205546.2396-2-sean.j.christopherson@intel.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-24Merge branch 'kvm-arm64/gic-v4.1' into kvmarm-master/nextMarc Zyngier7-34/+305
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-03-24KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfsMarc Zyngier1-1/+13
The vgic-state debugfs file could do with showing the pending state of the HW-backed SGIs. Plug it into the low-level code. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20200304203330.4967-24-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disableMarc Zyngier2-1/+12
Each time a Group-enable bit gets flipped, the state of these bits needs to be forwarded to the hardware. This is a pretty heavy handed operation, requiring all vcpus to reload their GICv4 configuration. It is thus implemented as a new request type. These enable bits are programmed into the HW by setting the VGrp{0,1}En fields of GICR_VPENDBASER when the vPEs are made resident again. Of course, we only support Group-1 for now... Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-22-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributorMarc Zyngier2-2/+49
The GICv4.1 architecture gives the hypervisor the option to let the guest choose whether it wants the good old SGIs with an active state, or the new, HW-based ones that do not have one. For this, plumb the configuration of SGIs into the GICv3 MMIO handling, present the GICD_TYPER2.nASSGIcap to the guest, and handle the GICD_CTLR.nASSGIreq setting. In order to be able to deal with the restore of a guest, also apply the GICD_CTLR.nASSGIreq setting at first run so that we can move the restored SGIs to the HW if that's what the guest had selected in a previous life. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-21-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interruptsMarc Zyngier2-0/+99
In order to let a guest buy in the new, active-less SGIs, we need to be able to switch between the two modes. Handle this by stopping all guest activity, transfer the state from one mode to the other, and resume the guest. Nothing calls this code so far, but a later patch will plug it into the MMIO emulation. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-20-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Add direct injection capability to SGI registersMarc Zyngier2-8/+107
Most of the GICv3 emulation code that deals with SGIs now has to be aware of the v4.1 capabilities in order to benefit from it. Add such support, keyed on the interrupt having the hw flag set and being a SGI. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20200304203330.4967-19-maz@kernel.org
2020-03-24KVM: arm64: GICv4.1: Let doorbells be auto-enabledMarc Zyngier1-1/+8
As GICv4.1 understands the life cycle of doorbells (instead of just randomly firing them at the most inconvenient time), just enable them at irq_request time, and be done with it. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20200304203330.4967-18-maz@kernel.org
2020-03-24irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction layerMarc Zyngier2-21/+17
In order to hide some of the differences between v4.0 and v4.1, move the doorbell management out of the KVM code, and into the GICv4-specific layer. This allows the calling code to ask for the doorbell when blocking, and otherwise to leave the doorbell permanently disabled. This matches the v4.1 code perfectly, and only results in a minor refactoring of the v4.0 code. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20200304203330.4967-14-maz@kernel.org
2020-03-16KVM: Drop largepages_enabled and its accessor/mutatorSean Christopherson1-13/+0
Drop largepages_enabled, kvm_largepages_enabled() and kvm_disable_largepages() now that all users are gone. Note, largepages_enabled was an x86-only flag that got left in common KVM code when KVM gained support for multiple architectures. No functional change intended. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Drop gfn_to_pfn_atomic()Peter Xu1-6/+0
It's never used anywhere now. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: x86: enable dirty log gradually in small chunksJay Zhou1-7/+17
It could take kvm->mmu_lock for an extended period of time when enabling dirty log for the first time. The main cost is to clear all the D-bits of last level SPTEs. This situation can benefit from manual dirty log protect as well, which can reduce the mmu_lock time taken. The sequence is like this: 1. Initialize all the bits of the dirty bitmap to 1 when enabling dirty log for the first time 2. Only write protect the huge pages 3. KVM_GET_DIRTY_LOG returns the dirty bitmap info 4. KVM_CLEAR_DIRTY_LOG will clear D-bit for each of the leaf level SPTEs gradually in small chunks Under the Intel(R) Xeon(R) Gold 6152 CPU @ 2.10GHz environment, I did some tests with a 128G windows VM and counted the time taken of memory_global_dirty_log_start, here is the numbers: VM Size Before After optimization 128G 460ms 10ms Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Remove unnecessary asm/kvm_host.h includesPeter Xu1-1/+0
Remove includes of asm/kvm_host.h from files that already include linux/kvm_host.h to make it more obvious that there is no ordering issue between the two headers. linux/kvm_host.h includes asm/kvm_host.h to pick up architecture specific settings, and this will never change, i.e. including asm/kvm_host.h after linux/kvm_host.h may seem problematic, but in practice is simply redundant. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Dynamically size memslot array based on number of used slotsSean Christopherson1-3/+28
Now that the memslot logic doesn't assume memslots are always non-NULL, dynamically size the array of memslots instead of unconditionally allocating memory for the maximum number of memslots. Note, because a to-be-deleted memslot must first be invalidated, the array size cannot be immediately reduced when deleting a memslot. However, consecutive deletions will realize the memory savings, i.e. a second deletion will trim the entry. Tested-by: Christoffer Dall <christoffer.dall@arm.com> Tested-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Terminate memslot walks via used_slotsSean Christopherson2-54/+165
Refactor memslot handling to treat the number of used slots as the de facto size of the memslot array, e.g. return NULL from id_to_memslot() when an invalid index is provided instead of relying on npages==0 to detect an invalid memslot. Rework the sorting and walking of memslots in advance of dynamically sizing memslots to aid bisection and debug, e.g. with luck, a bug in the refactoring will bisect here and/or hit a WARN instead of randomly corrupting memory. Alternatively, a global null/invalid memslot could be returned, i.e. so callers of id_to_memslot() don't have to explicitly check for a NULL memslot, but that approach runs the risk of introducing difficult-to- debug issues, e.g. if the global null slot is modified. Constifying the return from id_to_memslot() to combat such issues is possible, but would require a massive refactoring of arch specific code and would still be susceptible to casting shenanigans. Add function comments to update_memslots() and search_memslots() to explicitly (and loudly) state how memslots are sorted. Opportunistically stuff @hva with a non-canonical value when deleting a private memslot on x86 to detect bogus usage of the freed slot. No functional change intended. Tested-by: Christoffer Dall <christoffer.dall@arm.com> Tested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Ensure validity of memslot with respect to kvm_get_dirty_log()Sean Christopherson1-8/+19
Rework kvm_get_dirty_log() so that it "returns" the associated memslot on success. A future patch will rework memslot handling such that id_to_memslot() can return NULL, returning the memslot makes it more obvious that the validity of the memslot has been verified, i.e. precludes the need to add validity checks in the arch code that are technically unnecessary. To maintain ordering in s390, move the call to kvm_arch_sync_dirty_log() from s390's kvm_vm_ioctl_get_dirty_log() to the new kvm_get_dirty_log(). This is a nop for PPC, the only other arch that doesn't select KVM_GENERIC_DIRTYLOG_READ_PROTECT, as its sync_dirty_log() is empty. Ideally, moving the sync_dirty_log() call would be done in a separate patch, but it can't be done in a follow-on patch because that would temporarily break s390's ordering. Making the move in a preparatory patch would be functionally correct, but would create an odd scenario where the moved sync_dirty_log() would operate on a "different" memslot due to consuming the result of a different id_to_memslot(). The memslot couldn't actually be different as slots_lock is held, but the code is confusing enough as it is, i.e. moving sync_dirty_log() in this patch is the lesser of all evils. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Provide common implementation for generic dirty log functionsSean Christopherson2-64/+75
Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code. The arch specific implemenations are extremely similar, differing only in whether the dirty log needs to be sync'd from hardware (x86) and how the TLBs are flushed. Add new arch hooks to handle sync and TLB flush; the sync will also be used for non-generic dirty log support in a future patch (s390). The ulterior motive for providing a common implementation is to eliminate the dependency between arch and common code with respect to the memslot referenced by the dirty log, i.e. to make it obvious in the code that the validity of the memslot is guaranteed, as a future patch will rework memslot handling such that id_to_memslot() can return NULL. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Clean up local variable usage in __kvm_set_memory_region()Sean Christopherson1-24/+26
Clean up __kvm_set_memory_region() to achieve several goals: - Remove local variables that serve no real purpose - Improve the readability of the code - Better show the relationship between the 'old' and 'new' memslot - Prepare for dynamically sizing memslots - Document subtle gotchas (via comments) Note, using 'tmp' to hold the initial memslot is not strictly necessary at this juncture, e.g. 'old' could be directly copied from id_to_memslot(), but keep the pointer usage as id_to_memslot() will be able to return a NULL pointer once memslots are dynamically sized. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Simplify kvm_free_memslot() and all its descendentsSean Christopherson2-13/+8
Now that all callers of kvm_free_memslot() pass NULL for @dont, remove the param from the top-level routine and all arch's implementations. No functional change intended. Tested-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Move memslot deletion to helper functionSean Christopherson1-29/+46
Move memslot deletion into its own routine so that the success path for other memslot updates does not need to use kvm_free_memslot(), i.e. can explicitly destroy the dirty bitmap when necessary. This paves the way for dropping @dont from kvm_free_memslot(), i.e. all callers now pass NULL for @dont. Add a comment above the code to make a copy of the existing memslot prior to deletion, it is not at all obvious that the pointer will become stale during sorting and/or installation of new memslots. Note, kvm_arch_commit_memory_region() allows an architecture to free resources when moving a memslot or changing its flags, e.g. x86 frees its arch specific memslot metadata during commit_memory_region(). Acked-by: Christoffer Dall <christoffer.dall@arm.com> Tested-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Drop "const" attribute from old memslot in commit_memory_region()Sean Christopherson2-2/+2
Drop the "const" attribute from @old in kvm_arch_commit_memory_region() to allow arch specific code to free arch specific resources in the old memslot without having to cast away the attribute. Freeing resources in kvm_arch_commit_memory_region() paves the way for simplifying kvm_free_memslot() by eliminating the last usage of its @dont param. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Move setting of memslot into helper routineSean Christopherson1-43/+63
Split out the core functionality of setting a memslot into a separate helper in preparation for moving memslot deletion into its own routine. Tested-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Refactor error handling for setting memory regionSean Christopherson1-22/+18
Replace a big pile o' gotos with returns to make it more obvious what error code is being returned, and to prepare for refactoring the functional, i.e. post-checks, portion of __kvm_set_memory_region(). Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Explicitly free allocated-but-unused dirty bitmapSean Christopherson1-3/+4
Explicitly free an allocated-but-unused dirty bitmap instead of relying on kvm_free_memslot() if an error occurs in __kvm_set_memory_region(). There is no longer a need to abuse kvm_free_memslot() to free arch specific resources as arch specific code is now called only after the common flow is guaranteed to succeed. Arch code can still fail, but it's responsible for its own cleanup in that case. Eliminating the error path's abuse of kvm_free_memslot() paves the way for simplifying kvm_free_memslot(), i.e. dropping its @dont param. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Drop kvm_arch_create_memslot()Sean Christopherson2-20/+7
Remove kvm_arch_create_memslot() now that all arch implementations are effectively nops. Removing kvm_arch_create_memslot() eliminates the possibility for arch specific code to allocate memory prior to setting a memslot, which sets the stage for simplifying kvm_free_memslot(). Cc: Janosch Frank <frankja@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Don't free new memslot if allocation of said memslot failsSean Christopherson1-1/+1
The two implementations of kvm_arch_create_memslot() in x86 and PPC are both good citizens and free up all local resources if creation fails. Return immediately (via a superfluous goto) instead of calling kvm_free_memslot(). Note, the call to kvm_free_memslot() is effectively an expensive nop in this case as there are no resources to be freed. No functional change intended. Acked-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: Reinstall old memslots if arch preparation failsSean Christopherson1-11/+12
Reinstall the old memslots if preparing the new memory region fails after invalidating a to-be-{re}moved memslot. Remove the superfluous 'old_memslots' variable so that it's somewhat clear that the error handling path needs to free the unused memslots, not simply the 'old' memslots. Fixes: bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update") Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16KVM: arm64: Use the correct timer structure to access the physical counterKarimAllah Ahmed1-1/+1
Use the physical timer structure when reading the physical counter instead of using the virtual timer structure. Thankfully, nothing is accessing this code path yet (at least not until we enable save/restore of the physical counter). It doesn't hurt for this to be correct though. Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> [maz: amended commit log] Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Fixes: 84135d3d18da ("KVM: arm/arm64: consolidate arch timer trap handlers") Link: https://lore.kernel.org/r/1584351546-5018-1-git-send-email-karahmed@amazon.de
2020-02-28Merge tag 'kvmarm-fixes-5.6-1' of ↵Paolo Bonzini2-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm fixes for 5.6, take #1 - Fix compilation on 32bit - Move VHE guest entry/exit into the VHE-specific entry code - Make sure all functions called by the non-VHE HYP code is tagged as __always_inline
2020-02-17kvm: arm/arm64: Fold VHE entry/exit work into kvm_vcpu_run_vhe()Mark Rutland1-2/+0
With VHE, running a vCPU always requires the sequence: 1. kvm_arm_vhe_guest_enter(); 2. kvm_vcpu_run_vhe(); 3. kvm_arm_vhe_guest_exit() ... and as we invoke this from the shared arm/arm64 KVM code, 32-bit arm has to provide stubs for all three functions. To simplify the common code, and make it easier to make further modifications to the arm64-specific portions in the near future, let's fold kvm_arm_vhe_guest_enter() and kvm_arm_vhe_guest_exit() into kvm_vcpu_run_vhe(). The 32-bit stubs for kvm_arm_vhe_guest_enter() and kvm_arm_vhe_guest_exit() are removed, as they are no longer used. The 32-bit stub for kvm_vcpu_run_vhe() is left as-is. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200210114757.2889-1-mark.rutland@arm.com
2020-02-12KVM: Disable preemption in kvm_get_running_vcpu()Marc Zyngier2-15/+13
Accessing a per-cpu variable only makes sense when preemption is disabled (and the kernel does check this when the right debug options are switched on). For kvm_get_running_vcpu(), it is fine to return the value after re-enabling preemption, as the preempt notifiers will make sure that this is kept consistent across task migration (the comment above the function hints at it, but lacks the crucial preemption management). While we're at it, move the comment from the ARM code, which explains why the whole thing works. Fixes: 7495e22bb165 ("KVM: Move running VCPU from ARM to common code"). Cc: Paolo Bonzini <pbonzini@redhat.com> Reported-by: Zenghui Yu <yuzenghui@huawei.com> Tested-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/318984f6-bc36-33a3-abc6-bf2295974b06@huawei.com Message-id: <20200207163410.31276-1-maz@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-05KVM: fix overflow of zero page refcount with ksm runningZhuang Yanying1-0/+1
We are testing Virtual Machine with KSM on v5.4-rc2 kernel, and found the zero_page refcount overflow. The cause of refcount overflow is increased in try_async_pf (get_user_page) without being decreased in mmu_set_spte() while handling ept violation. In kvm_release_pfn_clean(), only unreserved page will call put_page. However, zero page is reserved. So, as well as creating and destroy vm, the refcount of zero page will continue to increase until it overflows. step1: echo 10000 > /sys/kernel/pages_to_scan/pages_to_scan echo 1 > /sys/kernel/pages_to_scan/run echo 1 > /sys/kernel/pages_to_scan/use_zero_pages step2: just create several normal qemu kvm vms. And destroy it after 10s. Repeat this action all the time. After a long period of time, all domains hang because of the refcount of zero page overflow. Qemu print error log as follow: … error: kvm run failed Bad address EAX=00006cdc EBX=00000008 ECX=80202001 EDX=078bfbfd ESI=ffffffff EDI=00000000 EBP=00000008 ESP=00006cc4 EIP=000efd75 EFL=00010002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA] SS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] DS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] FS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] GS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy GDT= 000f7070 00000037 IDT= 000f70ae 00000000 CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=00000000ffff0ff0 DR7=0000000000000400 EFER=0000000000000000 Code=00 01 00 00 00 e9 e8 00 00 00 c7 05 4c 55 0f 00 01 00 00 00 <8b> 35 00 00 01 00 8b 3d 04 00 01 00 b8 d8 d3 00 00 c1 e0 08 0c ea a3 00 00 01 00 c7 05 04 … Meanwhile, a kernel warning is departed. [40914.836375] WARNING: CPU: 3 PID: 82067 at ./include/linux/mm.h:987 try_get_page+0x1f/0x30 [40914.836412] CPU: 3 PID: 82067 Comm: CPU 0/KVM Kdump: loaded Tainted: G OE 5.2.0-rc2 #5 [40914.836415] RIP: 0010:try_get_page+0x1f/0x30 [40914.836417] Code: 40 00 c3 0f 1f 84 00 00 00 00 00 48 8b 47 08 a8 01 75 11 8b 47 34 85 c0 7e 10 f0 ff 47 34 b8 01 00 00 00 c3 48 8d 78 ff eb e9 <0f> 0b 31 c0 c3 66 90 66 2e 0f 1f 84 00 0 0 00 00 00 48 8b 47 08 a8 [40914.836418] RSP: 0018:ffffb4144e523988 EFLAGS: 00010286 [40914.836419] RAX: 0000000080000000 RBX: 0000000000000326 RCX: 0000000000000000 [40914.836420] RDX: 0000000000000000 RSI: 00004ffdeba10000 RDI: ffffdf07093f6440 [40914.836421] RBP: ffffdf07093f6440 R08: 800000424fd91225 R09: 0000000000000000 [40914.836421] R10: ffff9eb41bfeebb8 R11: 0000000000000000 R12: ffffdf06bbd1e8a8 [40914.836422] R13: 0000000000000080 R14: 800000424fd91225 R15: ffffdf07093f6440 [40914.836423] FS: 00007fb60ffff700(0000) GS:ffff9eb4802c0000(0000) knlGS:0000000000000000 [40914.836425] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [40914.836426] CR2: 0000000000000000 CR3: 0000002f220e6002 CR4: 00000000003626e0 [40914.836427] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [40914.836427] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [40914.836428] Call Trace: [40914.836433] follow_page_pte+0x302/0x47b [40914.836437] __get_user_pages+0xf1/0x7d0 [40914.836441] ? irq_work_queue+0x9/0x70 [40914.836443] get_user_pages_unlocked+0x13f/0x1e0 [40914.836469] __gfn_to_pfn_memslot+0x10e/0x400 [kvm] [40914.836486] try_async_pf+0x87/0x240 [kvm] [40914.836503] tdp_page_fault+0x139/0x270 [kvm] [40914.836523] kvm_mmu_page_fault+0x76/0x5e0 [kvm] [40914.836588] vcpu_enter_guest+0xb45/0x1570 [kvm] [40914.836632] kvm_arch_vcpu_ioctl_run+0x35d/0x580 [kvm] [40914.836645] kvm_vcpu_ioctl+0x26e/0x5d0 [kvm] [40914.836650] do_vfs_ioctl+0xa9/0x620 [40914.836653] ksys_ioctl+0x60/0x90 [40914.836654] __x64_sys_ioctl+0x16/0x20 [40914.836658] do_syscall_64+0x5b/0x180 [40914.836664] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [40914.836666] RIP: 0033:0x7fb61cb6bfc7 Signed-off-by: LinFeng <linfeng23@huawei.com> Signed-off-by: Zhuang Yanying <ann.zhuangyanying@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 03:59:33 +0000