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authorLadi Prosek <lprosek@redhat.com>2017-08-07 10:57:03 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2017-09-19 14:09:33 +0200
commitd72bc7f6f8a397790abee4a25ba1b8c35dd2b841 (patch)
treeae611f5b69b997a2f71f63e2b5c5fad9eba2ba7c /target
parent4bb95b82df7ea4a1c7de15649dd16a70a19e6bab (diff)
i386/kvm: advertise Hyper-V frequency MSRs
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> Reviewed-by: David Hildenbrand <david@redhat.com> Message-Id: <20170807085703.32267-5-lprosek@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target')
-rw-r--r--target/i386/kvm.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 2dc01c9973..739334a5a6 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;
}
}
}