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KVM: X86: Provide a capability to disable cstate msr read intercepts

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Allow guest reads CORE cstate when exposing host CPU power management capabilities
to the guest. PKG cstate is restricted to avoid a guest to get the whole package
information in multi-tenant scenario.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Wanpeng Li 2019-05-21 14:06:53 +08:00 committed by Paolo Bonzini
parent 8ffdaa7f49
commit b51700632e
7 changed files with 23 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Documentation/virtual/kvm/api.txt
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@ -4894,6 +4894,7 @@ Valid bits in args[0] are
#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
#define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
#define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3)
Enabling this capability on a VM provides userspace with a way to no
longer intercept some instructions for improved latency in some

1
arch/x86/include/asm/kvm_host.h
View File

@ -882,6 +882,7 @@ struct kvm_arch {
bool mwait_in_guest;
bool hlt_in_guest;
bool pause_in_guest;
bool cstate_in_guest;
unsigned long irq_sources_bitmap;
s64 kvmclock_offset;

6
arch/x86/kvm/vmx/vmx.c
View File

@ -6637,6 +6637,12 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_CS, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_ESP, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_EIP, MSR_TYPE_RW);
if (kvm_cstate_in_guest(kvm)) {
vmx_disable_intercept_for_msr(msr_bitmap, MSR_CORE_C1_RES, MSR_TYPE_R);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_CORE_C3_RESIDENCY, MSR_TYPE_R);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_CORE_C6_RESIDENCY, MSR_TYPE_R);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_CORE_C7_RESIDENCY, MSR_TYPE_R);
}
vmx->msr_bitmap_mode = 0;
vmx->loaded_vmcs = &vmx->vmcs01;

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

@ -3098,7 +3098,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = KVM_CLOCK_TSC_STABLE;
break;
case KVM_CAP_X86_DISABLE_EXITS:
r |= KVM_X86_DISABLE_EXITS_HLT | KVM_X86_DISABLE_EXITS_PAUSE;
r |= KVM_X86_DISABLE_EXITS_HLT | KVM_X86_DISABLE_EXITS_PAUSE |
KVM_X86_DISABLE_EXITS_CSTATE;
if(kvm_can_mwait_in_guest())
r |= KVM_X86_DISABLE_EXITS_MWAIT;
break;
@ -4615,6 +4616,8 @@ split_irqchip_unlock:
kvm->arch.hlt_in_guest = true;
if (cap->args[0] & KVM_X86_DISABLE_EXITS_PAUSE)
kvm->arch.pause_in_guest = true;
if (cap->args[0] & KVM_X86_DISABLE_EXITS_CSTATE)
kvm->arch.cstate_in_guest = true;
r = 0;
break;
case KVM_CAP_MSR_PLATFORM_INFO:

5
arch/x86/kvm/x86.h
View File

@ -333,6 +333,11 @@ static inline bool kvm_pause_in_guest(struct kvm *kvm)
return kvm->arch.pause_in_guest;
}
static inline bool kvm_cstate_in_guest(struct kvm *kvm)
{
return kvm->arch.cstate_in_guest;
}
DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);
static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu)

4
include/uapi/linux/kvm.h
View File

@ -696,9 +696,11 @@ struct kvm_ioeventfd {
#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
#define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
#define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3)
#define KVM_X86_DISABLE_VALID_EXITS (KVM_X86_DISABLE_EXITS_MWAIT | \
KVM_X86_DISABLE_EXITS_HLT | \
KVM_X86_DISABLE_EXITS_PAUSE)
KVM_X86_DISABLE_EXITS_PAUSE | \
KVM_X86_DISABLE_EXITS_CSTATE)
/* for KVM_ENABLE_CAP */
struct kvm_enable_cap {

4
tools/include/uapi/linux/kvm.h
View File

@ -696,9 +696,11 @@ struct kvm_ioeventfd {
#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
#define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
#define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3)
#define KVM_X86_DISABLE_VALID_EXITS (KVM_X86_DISABLE_EXITS_MWAIT | \
KVM_X86_DISABLE_EXITS_HLT | \
KVM_X86_DISABLE_EXITS_PAUSE)
KVM_X86_DISABLE_EXITS_PAUSE | \
KVM_X86_DISABLE_EXITS_CSTATE)
/* for KVM_ENABLE_CAP */
struct kvm_enable_cap {