| Message ID | 1558082990-7822-1-git-send-email-wanpengli@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] KVM: x86: Disable intercept for CORE cstate read | expand |
On 17/05/19 10:49, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > 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. Hmm, I am not sure about this. I can see why it can be useful to run turbostat in the guest, but is it a good idea to share it with the guest, since it counts from machine reset rather than from VM reset? Maybe it could use a separate bit for KVM_CAP_X86_DISABLE_EXITS? Thanks, Paolo > 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> > --- > arch/x86/kvm/vmx/vmx.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 771d3bf..b0d6be5 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6615,6 +6615,12 @@ 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_mwait_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; >
On Mon, 20 May 2019 at 18:30, Paolo Bonzini <pbonzini@redhat.com> wrote: > > On 17/05/19 10:49, Wanpeng Li wrote: > > From: Wanpeng Li <wanpengli@tencent.com> > > > > 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. > > Hmm, I am not sure about this. I can see why it can be useful to run > turbostat in the guest, but is it a good idea to share it with the Yeah. > guest, since it counts from machine reset rather than from VM reset? I also saw amazon expose these in their nitro c5 instance. > > Maybe it could use a separate bit for KVM_CAP_X86_DISABLE_EXITS? It could be. Regards, Wanpeng Li
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 771d3bf..b0d6be5 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6615,6 +6615,12 @@ 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_mwait_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;