On Fri, Mar 16, 2018 at 06:00:19PM +0100, Vitaly Kuznetsov wrote: > KVM recently gained support for Hyper-V Reenlightenment MSRs which are > required to make KVM-on-Hyper-V enable TSC page clocksource to its guests > when INVTSC is not passed to it (and it is not passed by default in Qemu > as it effectively blocks migration). > > Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> > --- > Changes since v1: > - add vmstate_msr_hyperv_reenlightenment subsection to vmstate_x86_cpu > [Paolo Bonzini] > --- > target/i386/cpu.h | 3 +++ > target/i386/hyperv-proto.h | 9 ++++++++- > target/i386/kvm.c | 33 +++++++++++++++++++++++++++++++++ > target/i386/machine.c | 24 ++++++++++++++++++++++++ > 4 files changed, 68 insertions(+), 1 deletion(-) > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 2e2bab5ff3..0b1b556a56 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -1174,6 +1174,9 @@ typedef struct CPUX86State { > uint64_t msr_hv_synic_sint[HV_SINT_COUNT]; > uint64_t msr_hv_stimer_config[HV_STIMER_COUNT]; > uint64_t msr_hv_stimer_count[HV_STIMER_COUNT]; > + uint64_t msr_hv_reenlightenment_control; > + uint64_t msr_hv_tsc_emulation_control; > + uint64_t msr_hv_tsc_emulation_status; > > uint64_t msr_rtit_ctrl; > uint64_t msr_rtit_status; > diff --git a/target/i386/hyperv-proto.h b/target/i386/hyperv-proto.h > index cb4d7f2b7a..93352ebd2a 100644 > --- a/target/i386/hyperv-proto.h > +++ b/target/i386/hyperv-proto.h > @@ -35,7 +35,7 @@ > #define HV_RESET_AVAILABLE (1u << 7) > #define HV_REFERENCE_TSC_AVAILABLE (1u << 9) > #define HV_ACCESS_FREQUENCY_MSRS (1u << 11) > - > +#define HV_ACCESS_REENLIGHTENMENTS_CONTROL (1u << 13) > > /* > * HV_CPUID_FEATURES.EDX bits > @@ -129,6 +129,13 @@ > #define HV_X64_MSR_CRASH_CTL 0x40000105 > #define HV_CRASH_CTL_NOTIFY (1ull << 63) > > +/* > + * Reenlightenment notification MSRs > + */ > +#define HV_X64_MSR_REENLIGHTENMENT_CONTROL 0x40000106 > +#define HV_X64_MSR_TSC_EMULATION_CONTROL 0x40000107 > +#define HV_X64_MSR_TSC_EMULATION_STATUS 0x40000108 > + > /* > * Hypercall status code > */ > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index d23fff12f5..accf50eac3 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -90,6 +90,7 @@ 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_hv_reenlightenment; > static bool has_msr_xss; > static bool has_msr_spec_ctrl; > static bool has_msr_smi_count; > @@ -653,6 +654,11 @@ 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 (has_msr_hv_reenlightenment) { > + env->features[FEAT_HYPERV_EAX] |= > + HV_ACCESS_REENLIGHTENMENTS_CONTROL; > + }
Can you please add a matching comment to the definition of feature_word_info[FEAT_HYPERV_EAX].feat_names[]? Also there appears to be no cpu property to turn this on/off, does it? It's enabled based only on the support in the KVM it's running against. So I guess we may have a problem migrating between the hosts with different KVM versions, one supporting it and the other not. (This is also a problem with has_msr_hv_frequencies, and is in general a long-standing issue of hv_* properties being done differently from the rest of CPUID features.) Thanks, Roman.