[PATCH RFC 12/22] KVM: x86: hyper-v: Honor HV_ACCESS_FREQUENCY_MSRS privilege bit
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: 2021-04-13 12:28:09
Also in:
kvm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm x86 hyper-v (kvm/hyper-v), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Vitaly Kuznetsov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
HV_X64_MSR_TSC_FREQUENCY/HV_X64_MSR_APIC_FREQUENCY are only available to guest when HV_ACCESS_FREQUENCY_MSRS bit is exposed. Note, writing to HV_X64_MSR_TSC_FREQUENCY/HV_X64_MSR_APIC_FREQUENCY is unsupported so kvm_hv_set_msr() doesn't need an additional check. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/kvm/hyperv.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 9c4454873e00..e92a1109ad9b 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c@@ -1637,9 +1637,17 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, pdata, host); } case HV_X64_MSR_TSC_FREQUENCY: + if (unlikely(!host && !(hv_vcpu->cpuid_cache.features_eax & + HV_ACCESS_FREQUENCY_MSRS))) + return 1; + data = (u64)vcpu->arch.virtual_tsc_khz * 1000; break; case HV_X64_MSR_APIC_FREQUENCY: + if (unlikely(!host && !(hv_vcpu->cpuid_cache.features_eax & + HV_ACCESS_FREQUENCY_MSRS))) + return 1; + data = APIC_BUS_FREQUENCY; break; default:
--
2.30.2