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[Qemu-devel] [PATCH 2/2] i386/kvm: lower requirements for Hyper-V freque
From: |
Vitaly Kuznetsov |
Subject: |
[Qemu-devel] [PATCH 2/2] i386/kvm: lower requirements for Hyper-V frequency MSRs exposure |
Date: |
Mon, 12 Mar 2018 16:12:33 +0100 |
Requiring tsc_is_stable_and_known() is too restrictive: even without INVTCS
nested Hyper-V-on-KVM enables TSC pages for its guests e.g. when
Reenlightenment MSRs are present. Presence of frequency MSRs doesn't mean
these frequencies are stable, it just means they're available for reading.
Signed-off-by: Vitaly Kuznetsov <address@hidden>
---
target/i386/kvm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 21e06deaf1..43c521f61a 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -646,7 +646,7 @@ static int hyperv_handle_properties(CPUState *cs)
env->features[FEAT_HYPERV_EAX] |= HV_TIME_REF_COUNT_AVAILABLE;
env->features[FEAT_HYPERV_EAX] |= HV_REFERENCE_TSC_AVAILABLE;
- if (has_msr_hv_frequencies && tsc_is_stable_and_known(env)) {
+ if (has_msr_hv_frequencies && env->tsc_khz) {
env->features[FEAT_HYPERV_EAX] |= HV_ACCESS_FREQUENCY_MSRS;
env->features[FEAT_HYPERV_EDX] |= HV_FREQUENCY_MSRS_AVAILABLE;
}
--
2.14.3
[Qemu-devel] [PATCH 1/2] i386/kvm: add support for Hyper-V reenlightenment MSRs, Vitaly Kuznetsov, 2018/03/12