| Message ID | 20170807085703.32267-5-lprosek@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07.08.2017 10:57, Ladi Prosek wrote: > As of kernel commit eb82feea59d6 ("KVM: hyperv: support HV_X64_MSR_TSC_FREQUENCY > and HV_X64_MSR_APIC_FREQUENCY"), KVM supports two new MSRs which are required > for nested Hyper-V to read timestamps with RDTSC + TSC page. > > This commit makes QEMU advertise the MSRs with CPUID.40000003H:EAX[11] and > CPUID.40000003H:EDX[8] as specified in the Hyper-V TLFS and experimentally > verified on a Hyper-V host. The feature is enabled with the existing hv-time CPU > flag, and only if the TSC frequency is stable across migrations and known. > > Signed-off-by: Ladi Prosek <lprosek@redhat.com> > --- > target/i386/kvm.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index 2dc01c9..739334a 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -89,6 +89,7 @@ static bool has_msr_hv_vpindex; > static bool has_msr_hv_runtime; > static bool has_msr_hv_synic; > static bool has_msr_hv_stimer; > +static bool has_msr_hv_frequencies; > static bool has_msr_xss; > > static bool has_msr_architectural_pmu; > @@ -640,7 +641,13 @@ static int hyperv_handle_properties(CPUState *cs) > if (cpu->hyperv_time) { > env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE; > env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_TIME_REF_COUNT_AVAILABLE; > - env->features[FEAT_HYPERV_EAX] |= 0x200; > + env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_REFERENCE_TSC_AVAILABLE; this could even go into a separate patch. > + > + if (has_msr_hv_frequencies && tsc_is_stable_and_known(env)) { > + env->features[FEAT_HYPERV_EAX] |= HV_X64_ACCESS_FREQUENCY_MSRS; > + env->features[FEAT_HYPERV_EDX] |= > + HV_FEATURE_FREQUENCY_MSRS_AVAILABLE; > + } > } > if (cpu->hyperv_crash && has_msr_hv_crash) { > env->features[FEAT_HYPERV_EDX] |= HV_X64_GUEST_CRASH_MSR_AVAILABLE; > @@ -1134,6 +1141,9 @@ static int kvm_get_supported_msrs(KVMState *s) > case HV_X64_MSR_STIMER0_CONFIG: > has_msr_hv_stimer = true; > break; > + case HV_X64_MSR_TSC_FREQUENCY: > + has_msr_hv_frequencies = true; > + break; > } > } > } > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 2dc01c9..739334a 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -89,6 +89,7 @@ static bool has_msr_hv_vpindex; static bool has_msr_hv_runtime; static bool has_msr_hv_synic; static bool has_msr_hv_stimer; +static bool has_msr_hv_frequencies; static bool has_msr_xss; static bool has_msr_architectural_pmu; @@ -640,7 +641,13 @@ static int hyperv_handle_properties(CPUState *cs) if (cpu->hyperv_time) { env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE; env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_TIME_REF_COUNT_AVAILABLE; - env->features[FEAT_HYPERV_EAX] |= 0x200; + env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_REFERENCE_TSC_AVAILABLE; + + if (has_msr_hv_frequencies && tsc_is_stable_and_known(env)) { + env->features[FEAT_HYPERV_EAX] |= HV_X64_ACCESS_FREQUENCY_MSRS; + env->features[FEAT_HYPERV_EDX] |= + HV_FEATURE_FREQUENCY_MSRS_AVAILABLE; + } } if (cpu->hyperv_crash && has_msr_hv_crash) { env->features[FEAT_HYPERV_EDX] |= HV_X64_GUEST_CRASH_MSR_AVAILABLE; @@ -1134,6 +1141,9 @@ static int kvm_get_supported_msrs(KVMState *s) case HV_X64_MSR_STIMER0_CONFIG: has_msr_hv_stimer = true; break; + case HV_X64_MSR_TSC_FREQUENCY: + has_msr_hv_frequencies = true; + break; } } }
As of kernel commit eb82feea59d6 ("KVM: hyperv: support HV_X64_MSR_TSC_FREQUENCY and HV_X64_MSR_APIC_FREQUENCY"), KVM supports two new MSRs which are required for nested Hyper-V to read timestamps with RDTSC + TSC page. This commit makes QEMU advertise the MSRs with CPUID.40000003H:EAX[11] and CPUID.40000003H:EDX[8] as specified in the Hyper-V TLFS and experimentally verified on a Hyper-V host. The feature is enabled with the existing hv-time CPU flag, and only if the TSC frequency is stable across migrations and known. Signed-off-by: Ladi Prosek <lprosek@redhat.com> --- target/i386/kvm.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)