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i386/hyperv: error out if features requested but unsupported

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In order to guarantee compatibility on migration, QEMU should have
complete control over the features it announces to the guest via CPUID.

However, for a number of Hyper-V-related cpu properties, if the
corresponding feature is not supported by the underlying KVM, the
propery is silently ignored and the feature is not announced to the
guest.

Refuse to start with an error instead.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Message-Id: <20180330170209.20627-3-rkagan@virtuozzo.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Roman Kagan 2018-03-30 20:02:09 +03:00 committed by Paolo Bonzini
parent 9445597b6a
commit 1221f15041
1 changed files with 34 additions and 9 deletions
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43
target/i386/kvm.c
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@ -632,11 +632,6 @@ static int hyperv_handle_properties(CPUState *cs)
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
if (cpu->hyperv_time &&
kvm_check_extension(cs->kvm_state, KVM_CAP_HYPERV_TIME) <= 0) {
cpu->hyperv_time = false;
}
if (cpu->hyperv_relaxed_timing) {
env->features[FEAT_HYPERV_EAX] |= HV_HYPERCALL_AVAILABLE;
}
@ -645,6 +640,12 @@ static int hyperv_handle_properties(CPUState *cs)
env->features[FEAT_HYPERV_EAX] |= HV_APIC_ACCESS_AVAILABLE;
}
if (cpu->hyperv_time) {
if (kvm_check_extension(cs->kvm_state, KVM_CAP_HYPERV_TIME) <= 0) {
fprintf(stderr, "Hyper-V clocksources "
"(requested by 'hv-time' cpu flag) "
"are not supported by kernel\n");
return -ENOSYS;
}
env->features[FEAT_HYPERV_EAX] |= HV_HYPERCALL_AVAILABLE;
env->features[FEAT_HYPERV_EAX] |= HV_TIME_REF_COUNT_AVAILABLE;
env->features[FEAT_HYPERV_EAX] |= HV_REFERENCE_TSC_AVAILABLE;
@ -659,17 +660,41 @@ static int hyperv_handle_properties(CPUState *cs)
env->features[FEAT_HYPERV_EAX] |= HV_ACCESS_FREQUENCY_MSRS;
env->features[FEAT_HYPERV_EDX] |= HV_FREQUENCY_MSRS_AVAILABLE;
}
if (cpu->hyperv_crash && has_msr_hv_crash) {
if (cpu->hyperv_crash) {
if (!has_msr_hv_crash) {
fprintf(stderr, "Hyper-V crash MSRs "
"(requested by 'hv-crash' cpu flag) "
"are not supported by kernel\n");
return -ENOSYS;
}
env->features[FEAT_HYPERV_EDX] |= HV_GUEST_CRASH_MSR_AVAILABLE;
}
env->features[FEAT_HYPERV_EDX] |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;
if (cpu->hyperv_reset && has_msr_hv_reset) {
if (cpu->hyperv_reset) {
if (!has_msr_hv_reset) {
fprintf(stderr, "Hyper-V reset MSR "
"(requested by 'hv-reset' cpu flag) "
"is not supported by kernel\n");
return -ENOSYS;
}
env->features[FEAT_HYPERV_EAX] |= HV_RESET_AVAILABLE;
}
if (cpu->hyperv_vpindex && has_msr_hv_vpindex) {
if (cpu->hyperv_vpindex) {
if (!has_msr_hv_vpindex) {
fprintf(stderr, "Hyper-V VP_INDEX MSR "
"(requested by 'hv-vpindex' cpu flag) "
"is not supported by kernel\n");
return -ENOSYS;
}
env->features[FEAT_HYPERV_EAX] |= HV_VP_INDEX_AVAILABLE;
}
if (cpu->hyperv_runtime && has_msr_hv_runtime) {
if (cpu->hyperv_runtime) {
if (!has_msr_hv_runtime) {
fprintf(stderr, "Hyper-V VP_RUNTIME MSR "
"(requested by 'hv-runtime' cpu flag) "
"is not supported by kernel\n");
return -ENOSYS;
}
env->features[FEAT_HYPERV_EAX] |= HV_VP_RUNTIME_AVAILABLE;
}
if (cpu->hyperv_synic) {