diff options
| -rw-r--r-- | arch/powerpc/include/asm/hmi.h | 45 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 4 | ||||
| -rw-r--r-- | arch/powerpc/kernel/hmi.c | 56 | ||||
| -rw-r--r-- | arch/powerpc/kernel/idle_power7.S | 5 | ||||
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 5 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 37 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_ras.c | 176 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 65 |
10 files changed, 396 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/hmi.h b/arch/powerpc/include/asm/hmi.h new file mode 100644 index 000000000000..88b4901ac4ee --- /dev/null +++ b/arch/powerpc/include/asm/hmi.h @@ -0,0 +1,45 @@ +/* + * Hypervisor Maintenance Interrupt header file. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. + * + * Copyright 2015 IBM Corporation + * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> + */ + +#ifndef __ASM_PPC64_HMI_H__ +#define __ASM_PPC64_HMI_H__ + +#ifdef CONFIG_PPC_BOOK3S_64 + +#define CORE_TB_RESYNC_REQ_BIT 63 +#define MAX_SUBCORE_PER_CORE 4 + +/* + * sibling_subcore_state structure is used to co-ordinate all threads + * during HMI to avoid TB corruption. This structure is allocated once + * per each core and shared by all threads on that core. + */ +struct sibling_subcore_state { + unsigned long flags; + u8 in_guest[MAX_SUBCORE_PER_CORE]; +}; + +extern void wait_for_subcore_guest_exit(void); +extern void wait_for_tb_resync(void); +#else +static inline void wait_for_subcore_guest_exit(void) { } +static inline void wait_for_tb_resync(void) { } +#endif +#endif /* __ASM_PPC64_HMI_H__ */ diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 546540b91095..4b17bd058e01 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -25,6 +25,7 @@ #ifdef CONFIG_KVM_BOOK3S_64_HANDLER #include <asm/kvm_book3s_asm.h> #endif +#include <asm/hmi.h> register struct paca_struct *local_paca asm("r13"); @@ -181,6 +182,11 @@ struct paca_struct { */ u16 in_mce; u8 hmi_event_available; /* HMI event is available */ + /* + * Bitmap for sibling subcore status. See kvm/book3s_hv_ras.c for + * more details + */ + struct sibling_subcore_state *sibling_subcore_state; #endif /* Stuff for accurate time accounting */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 2da380fcc34c..6972a23433d3 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -41,7 +41,7 @@ obj-$(CONFIG_VDSO32) += vdso32/ obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_ppc970.o cpu_setup_pa6t.o obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_power.o -obj-$(CONFIG_PPC_BOOK3S_64) += mce.o mce_power.o +obj-$(CONFIG_PPC_BOOK3S_64) += mce.o mce_power.o hmi.o obj64-$(CONFIG_RELOCATABLE) += reloc_64.o obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o idle_book3e.o obj-$(CONFIG_PPC64) += vdso64/ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 4c9440629128..0eba47e074b9 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -680,6 +680,8 @@ _GLOBAL(__replay_interrupt) BEGIN_FTR_SECTION cmpwi r3,0xe80 beq h_doorbell_common + cmpwi r3,0xe60 + beq hmi_exception_common FTR_SECTION_ELSE cmpwi r3,0xa00 beq doorbell_super_common @@ -1172,7 +1174,7 @@ fwnmi_data_area: .globl hmi_exception_early hmi_exception_early: - EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0xe60) + EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST, 0xe62) mr r10,r1 /* Save r1 */ ld r1,PACAEMERGSP(r13) /* Use emergency stack */ subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */ diff --git a/arch/powerpc/kernel/hmi.c b/arch/powerpc/kernel/hmi.c new file mode 100644 index 000000000000..e3f738eb1cac --- /dev/null +++ b/arch/powerpc/kernel/hmi.c @@ -0,0 +1,56 @@ +/* + * Hypervisor Maintenance Interrupt (HMI) handling. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. + * + * Copyright 2015 IBM Corporation + * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> + */ + +#undef DEBUG + +#include <linux/types.h> +#include <linux/compiler.h> +#include <asm/paca.h> +#include <asm/hmi.h> + +void wait_for_subcore_guest_exit(void) +{ + int i; + + /* + * NULL bitmap pointer indicates that KVM module hasn't + * been loaded yet and hence no guests are running. + * If no KVM is in use, no need to co-ordinate among threads + * as all of them will always be in host and no one is going + * to modify TB other than the opal hmi handler. + * Hence, just return from here. + */ + if (!local_paca->sibling_subcore_state) + return; + + for (i = 0; i < MAX_SUBCORE_PER_CORE; i++) + while (local_paca->sibling_subcore_state->in_guest[i]) + cpu_relax(); +} + +void wait_for_tb_resync(void) +{ + if (!local_paca->sibling_subcore_state) + return; + + while (test_bit(CORE_TB_RESYNC_REQ_BIT, + &local_paca->sibling_subcore_state->flags)) + cpu_relax(); +} diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S index 470ceebd2d23..bb5112908fb2 100644 --- a/arch/powerpc/kernel/idle_power7.S +++ b/arch/powerpc/kernel/idle_power7.S @@ -270,8 +270,9 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \ ld r2,PACATOC(r13); \ ld r1,PACAR1(r13); \ std r3,ORIG_GPR3(r1); /* Save original r3 */ \ - li r0,OPAL_HANDLE_HMI; /* Pass opal token argument*/ \ - bl opal_call_realmode; \ + li r3,0; /* NULL argument */ \ + bl hmi_exception_realmode; \ + nop; \ ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \ 20: nop; diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 9229ba63c370..9ec95daccad9 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -60,6 +60,7 @@ #include <asm/switch_to.h> #include <asm/tm.h> #include <asm/debug.h> +#include <asm/hmi.h> #include <sysdev/fsl_pci.h> #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC) @@ -307,9 +308,13 @@ long hmi_exception_realmode(struct pt_regs *regs) { __this_cpu_inc(irq_stat.hmi_exceptions); + wait_for_subcore_guest_exit(); + if (ppc_md.hmi_exception_early) ppc_md.hmi_exception_early(regs); + wait_for_tb_resync(); + return 0; } diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index e20beae5ca7a..bc27c4d6383c 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -52,6 +52,7 @@ #include <asm/switch_to.h> #include <asm/smp.h> #include <asm/dbell.h> +#include <asm/hmi.h> #include <linux/gfp.h> #include <linux/vmalloc.h> #include <linux/highmem.h> @@ -3401,6 +3402,38 @@ static struct kvmppc_ops kvm_ops_hv = { .hcall_implemented = kvmppc_hcall_impl_hv, }; +static int kvm_init_subcore_bitmap(void) +{ + int i, j; + int nr_cores = cpu_nr_cores(); + struct sibling_subcore_state *sibling_subcore_state; + + for (i = 0; i < nr_cores; i++) { + int first_cpu = i * threads_per_core; + int node = cpu_to_node(first_cpu); + + /* Ignore if it is already allocated. */ + if (paca[first_cpu].sibling_subcore_state) + continue; + + sibling_subcore_state = + kmalloc_node(sizeof(struct sibling_subcore_state), + GFP_KERNEL, node); + if (!sibling_subcore_state) + return -ENOMEM; + + memset(sibling_subcore_state, 0, + sizeof(struct sibling_subcore_state)); + + for (j = 0; j < threads_per_core; j++) { + int cpu = first_cpu + j; + + paca[cpu].sibling_subcore_state = sibling_subcore_state; + } + } + return 0; +} + static int kvmppc_book3s_init_hv(void) { int r; @@ -3411,6 +3444,10 @@ static int kvmppc_book3s_init_hv(void) if (r < 0) return -ENODEV; + r = kvm_init_subcore_bitmap(); + if (r) + return r; + kvm_ops_hv.owner = THIS_MODULE; kvmppc_hv_ops = &kvm_ops_hv; diff --git a/arch/powerpc/kvm/book3s_hv_ras.c b/arch/powerpc/kvm/book3s_hv_ras.c index 93b5f5c9b445..0fa70a9618d7 100644 --- a/arch/powerpc/kvm/book3s_hv_ras.c +++ b/arch/powerpc/kvm/book3s_hv_ras.c @@ -13,6 +13,9 @@ #include <linux/kernel.h> #include <asm/opal.h> #include <asm/mce.h> +#include <asm/machdep.h> +#include <asm/cputhreads.h> +#include <asm/hmi.h> /* SRR1 bits for machine check on POWER7 */ #define SRR1_MC_LDSTERR (1ul << (63-42)) @@ -140,3 +143,176 @@ long kvmppc_realmode_machine_check(struct kvm_vcpu *vcpu) { return kvmppc_realmode_mc_power7(vcpu); } + +/* Check if dynamic split is in force and return subcore size accordingly. */ +static inline int kvmppc_cur_subcore_size(void) +{ + if (local_paca->kvm_hstate.kvm_split_mode) + return local_paca->kvm_hstate.kvm_split_mode->subcore_size; + + return threads_per_subcore; +} + +void kvmppc_subcore_enter_guest(void) +{ + int thread_id, subcore_id; + + thread_id = cpu_thread_in_core(local_paca->paca_index); + subcore_id = thread_id / kvmppc_cur_subcore_size(); + + local_paca->sibling_subcore_state->in_guest[subcore_id] = 1; +} + +void kvmppc_subcore_exit_guest(void) +{ + int thread_id, subcore_id; + + thread_id = cpu_thread_in_core(local_paca->paca_index); + subcore_id = thread_id / kvmppc_cur_subcore_size(); + + local_paca->sibling_subcore_state->in_guest[subcore_id] = 0; +} + +static bool kvmppc_tb_resync_required(void) +{ + if (test_and_set_bit(CORE_TB_RESYNC_REQ_BIT, + &local_paca->sibling_subcore_state->flags)) + return false; + + return true; +} + +static void kvmppc_tb_resync_done(void) +{ + clear_bit(CORE_TB_RESYNC_REQ_BIT, + &local_paca->sibling_subcore_state->flags); +} + +/* + * kvmppc_realmode_hmi_handler() is called only by primary thread during + * guest exit path. + * + * There are multiple reasons why HMI could occur, one of them is + * Timebase (TB) error. If this HMI is due to TB error, then TB would + * have been in stopped state. The opal hmi handler Will fix it and + * restore the TB value with host timebase value. For HMI caused due + * to non-TB errors, opal hmi handler will not touch/restore TB register + * and hence there won't be any change in TB value. + * + * Since we are not sure about the cause of this HMI, we can't be sure + * about the content of TB register whether it holds guest or host timebase + * value. Hence the idea is to resync the TB on every HMI, so that we + * know about the exact state of the TB value. Resync TB call will + * restore TB to host timebase. + * + * Things to consider: + * - On TB error, HMI interrupt is reported on all the threads of the core + * that has encountered TB error irrespective of split-core mode. + * - The very first thread on the core that get chance to fix TB error + * would rsync the TB with local chipTOD value. + * - The resync TB is a core level action i.e. it will sync all the TBs + * in that core independent of split-core mode. This means if we trigger + * TB sync from a thread from one subcore, it would affect TB values of + * sibling subcores of the same core. + * + * All threads need to co-ordinate before making opal hmi handler. + * All threads will use sibling_subcore_state->in_guest[] (shared by all + * threads in the core) in paca which holds information about whether + * sibling subcores are in Guest mode or host mode. The in_guest[] array + * is of size MAX_SUBCORE_PER_CORE=4, indexed using subcore id to set/unset + * subcore status. Only primary threads from each subcore is responsible + * to set/unset its designated array element while entering/exiting the + * guset. + * + * After invoking opal hmi handler call, one of the thread (of entire core) + * will need to resync the TB. Bit 63 from subcore state bitmap flags + * (sibling_subcore_state->flags) will be used to co-ordinate between + * primary threads to decide who takes up the responsibility. + * + * This is what we do: + * - Primary thread from each subcore tries to set resync required bit[63] + * of paca->sibling_subcore_state->flags. + * - The first primary thread that is able to set the flag takes the + * responsibility of TB resync. (Let us call it as thread leader) + * - All other threads which are in host will call + * wait_for_subcore_guest_exit() and wait for in_guest[0-3] from + * paca->sibling_subcore_state to get cleared. + * - All the primary thread will clear its subcore status from subcore + * state in_guest[] array respectively. + * - Once all primary threads clear in_guest[0-3], all of them will invoke + * opal hmi handler. + * - Now all threads will wait for TB resync to complete by invoking + * wait_for_tb_resync() except the thread leader. + * - Thread leader will do a TB resync by invoking opal_resync_timebase() + * call and the it will clear the resync required bit. + * - All other threads will now come out of resync wait loop and proceed + * with individual execution. + * - On return of this function, primary thread will signal all + * secondary threads to proceed. + * - All secondary threads will eventually call opal hmi handler on + * their exit path. + */ + +long kvmppc_realmode_hmi_handler(void) +{ + int ptid = local_paca->kvm_hstate.ptid; + bool resync_req; + + /* This is only called on primary thread. */ + BUG_ON(ptid != 0); + __this_cpu_inc(irq_stat.hmi_exceptions); + + /* + * By now primary thread has already completed guest->host + * partition switch but haven't signaled secondaries yet. + * All the secondary threads on this subcore is waiting + * for primary thread to signal them to go ahead. + * + * For threads from subcore which isn't in guest, they all will + * wait until all other subcores on this core exit the guest. + * + * Now set the resync required bit. If you are the first to + * set this bit then kvmppc_tb_resync_required() function will + * return true. For rest all other subcores + * kvmppc_tb_resync_required() will return false. + * + * If resync_req == true, then this thread is responsible to + * initiate TB resync after hmi handler has completed. + * All other threads on this core will wait until this thread + * clears the resync required bit flag. + */ + resync_req = kvmppc_tb_resync_required(); + + /* Reset the subcore status to indicate it has exited guest */ + kvmppc_subcore_exit_guest(); + + /* + * Wait for other subcores on this core to exit the guest. + * All the primary threads and threads from subcore that are + * not in guest will wait here until all subcores are out + * of guest context. + */ + wait_for_subcore_guest_exit(); + + /* + * At this point we are sure that primary threads from each + * subcore on this core have completed guest->host partition + * switch. Now it is safe to call HMI handler. + */ + if (ppc_md.hmi_exception_early) + ppc_md.hmi_exception_early(NULL); + + /* + * Check if this thread is responsible to resync TB. + * All other threads will wait until this thread completes the + * TB resync. + */ + if (resync_req) { + opal_resync_timebase(); + /* Reset TB resync req bit */ + kvmppc_tb_resync_done(); + } else { + wait_for_tb_resync(); + } + return 0; +} diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index e571ad277398..0d246fca157a 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -29,6 +29,7 @@ #include <asm/kvm_book3s_asm.h> #include <asm/book3s/64/mmu-hash.h> #include <asm/tm.h> +#include <asm/opal.h> #define VCPU_GPRS_TM(reg) (((reg) * ULONG_SIZE) + VCPU_GPR_TM) @@ -373,6 +374,18 @@ kvm_secondary_got_guest: lwsync std r0, HSTATE_KVM_VCORE(r13) + /* + * All secondaries exiting guest will fall through this path. + * Before proceeding, just check for HMI interrupt and + * invoke opal hmi handler. By now we are sure that the + * primary thread on this core/subcore has already made partition + * switch/TB resync and we are good to call opal hmi handler. + */ + cmpwi r12, BOOK3S_INTERRUPT_HMI + bne kvm_no_guest + + li r3,0 /* NULL argument */ + bl hmi_exception_realmode /* * At this point we have finished executing in the guest. * We need to wait for hwthread_req to become zero, since @@ -428,6 +441,22 @@ kvm_no_guest: */ kvm_unsplit_nap: /* + * When secondaries are napping in kvm_unsplit_nap() with + * hwthread_req = 1, HMI goes ignored even though subcores are + * already exited the guest. Hence HMI keeps waking up secondaries + * from nap in a loop and secondaries always go back to nap since + * no vcore is assigned to them. This makes impossible for primary + * thread to get hold of secondary threads resulting into a soft + * lockup in KVM path. + * + * Let us check if HMI is pending and handle it before we go to nap. + */ + cmpwi r12, BOOK3S_INTERRUPT_HMI + bne 55f + li r3, 0 /* NULL argument */ + bl hmi_exception_realmode +55: + /* * Ensure that secondary doesn't nap when it has * its vcore pointer set. */ @@ -601,6 +630,11 @@ BEGIN_FTR_SECTION mtspr SPRN_DPDES, r8 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) + /* Mark the subcore state as inside guest */ + bl kvmppc_subcore_enter_guest + nop + ld r5, HSTATE_KVM_VCORE(r13) + ld r4, HSTATE_KVM_VCPU(r13) li r0,1 stb r0,VCORE_IN_GUEST(r5) /* signal secondaries to continue */ @@ -1683,6 +1717,23 @@ BEGIN_FTR_SECTION mtspr SPRN_DPDES, r8 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) + /* If HMI, call kvmppc_realmode_hmi_handler() */ + cmpwi r12, BOOK3S_INTERRUPT_HMI + bne 27f + bl kvmppc_realmode_hmi_handler + nop + li r12, BOOK3S_INTERRUPT_HMI + /* + * At this point kvmppc_realmode_hmi_handler would have resync-ed + * the TB. Hence it is not required to subtract guest timebase + * offset from timebase. So, skip it. + * + * Also, do not call kvmppc_subcore_exit_guest() because it has + * been invoked as part of kvmppc_realmode_hmi_handler(). + */ + b 30f + +27: /* Subtract timebase offset from timebase */ ld r8,VCORE_TB_OFFSET(r5) cmpdi r8,0 @@ -1698,8 +1749,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) addis r8,r8,0x100 /* if so, increment upper 40 bits */ mtspr SPRN_TBU40,r8 +17: bl kvmppc_subcore_exit_guest + nop +30: ld r5,HSTATE_KVM_VCORE(r13) + ld r4,VCORE_KVM(r5) /* pointer to struct kvm */ + /* Reset PCR */ -17: ld r0, VCORE_PCR(r5) + ld r0, VCORE_PCR(r5) cmpdi r0, 0 beq 18f li r0, 0 @@ -2461,6 +2517,8 @@ BEGIN_FTR_SECTION cmpwi r6, 3 /* hypervisor doorbell? */ beq 3f END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) + cmpwi r6, 0xa /* Hypervisor maintenance ? */ + beq 4f li r3, 1 /* anything else, return 1 */ 0: blr @@ -2482,6 +2540,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) li r3, -1 blr + /* Woken up due to Hypervisor maintenance interrupt */ +4: li r12, BOOK3S_INTERRUPT_HMI + li r3, 1 + blr + /* * Determine what sort of external interrupt is pending (if any). * Returns: |