From f5f48ee15c2ee3e44cf429e34b16c6fa9b900246 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Wed, 30 Jun 2010 12:25:15 +0800 Subject: [PATCH] KVM: VMX: Execute WBINVD to keep data consistency with assigned devices Some guest device driver may leverage the "Non-Snoop" I/O, and explicitly WBINVD or CLFLUSH to a RAM space. Since migration may occur before WBINVD or CLFLUSH, we need to maintain data consistency either by: 1: flushing cache (wbinvd) when the guest is scheduled out if there is no wbinvd exit, or 2: execute wbinvd on all dirty physical CPUs when guest wbinvd exits. Signed-off-by: Yaozu (Eddie) Dong Signed-off-by: Sheng Yang Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/kvm_host.h | 6 +++++ arch/x86/kvm/emulate.c | 5 +++- arch/x86/kvm/svm.c | 7 ++++++ arch/x86/kvm/vmx.c | 10 +++++++- arch/x86/kvm/x86.c | 41 +++++++++++++++++++++++++++++++++ 5 files changed, 67 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index a57cdeacc4d2..2bda62485c4c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -358,6 +359,8 @@ struct kvm_vcpu_arch { /* fields used by HYPER-V emulation */ u64 hv_vapic; + + cpumask_var_t wbinvd_dirty_mask; }; struct kvm_arch { @@ -514,6 +517,8 @@ struct kvm_x86_ops { void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry); + bool (*has_wbinvd_exit)(void); + const struct trace_print_flags *exit_reasons_str; }; @@ -571,6 +576,7 @@ void kvm_emulate_cpuid(struct kvm_vcpu *vcpu); int kvm_emulate_halt(struct kvm_vcpu *vcpu); int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t address); int emulate_clts(struct kvm_vcpu *vcpu); +int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu); void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg); diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index abb8cec420a2..e8bdddc4509e 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3138,8 +3138,11 @@ twobyte_insn: emulate_clts(ctxt->vcpu); c->dst.type = OP_NONE; break; - case 0x08: /* invd */ case 0x09: /* wbinvd */ + kvm_emulate_wbinvd(ctxt->vcpu); + c->dst.type = OP_NONE; + break; + case 0x08: /* invd */ case 0x0d: /* GrpP (prefetch) */ case 0x18: /* Grp16 (prefetch/nop) */ c->dst.type = OP_NONE; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 587b99d37d44..56c9b6bd7655 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3424,6 +3424,11 @@ static bool svm_rdtscp_supported(void) return false; } +static bool svm_has_wbinvd_exit(void) +{ + return true; +} + static void svm_fpu_deactivate(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -3508,6 +3513,8 @@ static struct kvm_x86_ops svm_x86_ops = { .rdtscp_supported = svm_rdtscp_supported, .set_supported_cpuid = svm_set_supported_cpuid, + + .has_wbinvd_exit = svm_has_wbinvd_exit, }; static int __init svm_init(void) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 661c6e199b4a..4dfb1dc09c88 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -412,6 +412,12 @@ static inline bool cpu_has_virtual_nmis(void) return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS; } +static inline bool cpu_has_vmx_wbinvd_exit(void) +{ + return vmcs_config.cpu_based_2nd_exec_ctrl & + SECONDARY_EXEC_WBINVD_EXITING; +} + static inline bool report_flexpriority(void) { return flexpriority_enabled; @@ -3397,7 +3403,7 @@ static int handle_invlpg(struct kvm_vcpu *vcpu) static int handle_wbinvd(struct kvm_vcpu *vcpu) { skip_emulated_instruction(vcpu); - /* TODO: Add support for VT-d/pass-through device */ + kvm_emulate_wbinvd(vcpu); return 1; } @@ -4347,6 +4353,8 @@ static struct kvm_x86_ops vmx_x86_ops = { .rdtscp_supported = vmx_rdtscp_supported, .set_supported_cpuid = vmx_set_supported_cpuid, + + .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit, }; static int __init vmx_init(void) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 27322d341232..3d72fc067059 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1783,8 +1783,28 @@ out: return r; } +static void wbinvd_ipi(void *garbage) +{ + wbinvd(); +} + +static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu) +{ + return vcpu->kvm->arch.iommu_domain && + !(vcpu->kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY); +} + void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + /* Address WBINVD may be executed by guest */ + if (need_emulate_wbinvd(vcpu)) { + if (kvm_x86_ops->has_wbinvd_exit()) + cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask); + else if (vcpu->cpu != -1 && vcpu->cpu != cpu) + smp_call_function_single(vcpu->cpu, + wbinvd_ipi, NULL, 1); + } + kvm_x86_ops->vcpu_load(vcpu, cpu); if (unlikely(per_cpu(cpu_tsc_khz, cpu) == 0)) { unsigned long khz = cpufreq_quick_get(cpu); @@ -3660,6 +3680,21 @@ int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t address) return X86EMUL_CONTINUE; } +int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu) +{ + if (!need_emulate_wbinvd(vcpu)) + return X86EMUL_CONTINUE; + + if (kvm_x86_ops->has_wbinvd_exit()) { + smp_call_function_many(vcpu->arch.wbinvd_dirty_mask, + wbinvd_ipi, NULL, 1); + cpumask_clear(vcpu->arch.wbinvd_dirty_mask); + } + wbinvd(); + return X86EMUL_CONTINUE; +} +EXPORT_SYMBOL_GPL(kvm_emulate_wbinvd); + int emulate_clts(struct kvm_vcpu *vcpu) { kvm_x86_ops->set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~X86_CR0_TS)); @@ -5263,6 +5298,7 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu) vcpu->arch.time_page = NULL; } + free_cpumask_var(vcpu->arch.wbinvd_dirty_mask); fx_free(vcpu); kvm_x86_ops->vcpu_free(vcpu); } @@ -5392,7 +5428,12 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) } vcpu->arch.mcg_cap = KVM_MAX_MCE_BANKS; + if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask, GFP_KERNEL)) + goto fail_free_mce_banks; + return 0; +fail_free_mce_banks: + kfree(vcpu->arch.mce_banks); fail_free_lapic: kvm_free_lapic(vcpu); fail_mmu_destroy: -- 2.34.1