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KVM: VMX: Execute WBINVD to keep data consistency with assigned devices

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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 <eddie.dong@intel.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Sheng Yang 2010-06-30 12:25:15 +08:00 committed by Avi Kivity
parent cf3e3d3e19
commit f5f48ee15c
5 changed files with 67 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/include/asm/kvm_host.h
View File

@ -15,6 +15,7 @@
#include <linux/mm.h>
#include <linux/mmu_notifier.h>
#include <linux/tracepoint.h>
#include <linux/cpumask.h>
#include <linux/kvm.h>
#include <linux/kvm_para.h>
@ -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);

5
arch/x86/kvm/emulate.c
View File

@ -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;

7
arch/x86/kvm/svm.c
View File

@ -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)

10
arch/x86/kvm/vmx.c
View File

@ -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)

41
arch/x86/kvm/x86.c
View File

@ -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: