| Message ID | 20210426090644.2218834-2-hikalium@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/kvm: Virtual suspend time injection support | expand |
On Monday, 2021-04-26 at 18:06:40 +09, Hikaru Nishida wrote: > No functional change; just add documentation for > KVM_FEATURE_HOST_SUSPEND_TIME and its corresponding > MSR_KVM_HOST_SUSPEND_TIME to support virtual suspend timing injection in > later patches. > > Signed-off-by: Hikaru Nishida <hikalium@chromium.org> > --- > > Documentation/virt/kvm/cpuid.rst | 3 +++ > Documentation/virt/kvm/msr.rst | 29 +++++++++++++++++++++++++++++ > 2 files changed, 32 insertions(+) > > diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst > index cf62162d4be2..c7cb581b9a9b 100644 > --- a/Documentation/virt/kvm/cpuid.rst > +++ b/Documentation/virt/kvm/cpuid.rst > @@ -96,6 +96,9 @@ KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit > before using extended destination > ID bits in MSI address bits 11-5. > > +KVM_FEATURE_HOST_SUSPEND_TIME 16 host suspend time information > + is available at msr 0x4b564d08. > + > KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side > per-cpu warps are expected in > kvmclock > diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst > index e37a14c323d2..de96743245c9 100644 > --- a/Documentation/virt/kvm/msr.rst > +++ b/Documentation/virt/kvm/msr.rst > @@ -376,3 +376,32 @@ data: > write '1' to bit 0 of the MSR, this causes the host to re-scan its queue > and check if there are more notifications pending. The MSR is available > if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. > + > +MSR_KVM_HOST_SUSPEND_TIME: > + 0x4b564d08 > + > +data: > + 8-byte alignment physical address of a memory area which must be > + in guest RAM, plus an enable bit in bit 0. This memory is expected to > + hold a copy of the following structure:: > + > + struct kvm_host_suspend_time { > + __u64 suspend_time_ns; > + }; > + > + whose data will be filled in by the hypervisor. > + If the guest register this structure through the MSR write, the host > + will stop all the clocks including TSCs observed by the guest during > + the host's suspension and report the duration of suspend through this > + structure. Fields have the following meanings: > + > + host_suspend_time_ns: s/host_suspend_time_ns/suspend_time_ns/ > + Total number of nanoseconds passed during the host's suspend > + while the VM is running. This value will be increasing > + monotonically. > + > + Note that although MSRs are per-CPU entities, the effect of this > + particular MSR is global. > + > + Availability of this MSR must be checked via bit 16 in 0x4000001 cpuid > + leaf prior to usage. > -- > 2.31.1.498.g6c1eba8ee3d-goog dme.
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst index cf62162d4be2..c7cb581b9a9b 100644 --- a/Documentation/virt/kvm/cpuid.rst +++ b/Documentation/virt/kvm/cpuid.rst @@ -96,6 +96,9 @@ KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit before using extended destination ID bits in MSI address bits 11-5. +KVM_FEATURE_HOST_SUSPEND_TIME 16 host suspend time information + is available at msr 0x4b564d08. + KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side per-cpu warps are expected in kvmclock diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst index e37a14c323d2..de96743245c9 100644 --- a/Documentation/virt/kvm/msr.rst +++ b/Documentation/virt/kvm/msr.rst @@ -376,3 +376,32 @@ data: write '1' to bit 0 of the MSR, this causes the host to re-scan its queue and check if there are more notifications pending. The MSR is available if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. + +MSR_KVM_HOST_SUSPEND_TIME: + 0x4b564d08 + +data: + 8-byte alignment physical address of a memory area which must be + in guest RAM, plus an enable bit in bit 0. This memory is expected to + hold a copy of the following structure:: + + struct kvm_host_suspend_time { + __u64 suspend_time_ns; + }; + + whose data will be filled in by the hypervisor. + If the guest register this structure through the MSR write, the host + will stop all the clocks including TSCs observed by the guest during + the host's suspension and report the duration of suspend through this + structure. Fields have the following meanings: + + host_suspend_time_ns: + Total number of nanoseconds passed during the host's suspend + while the VM is running. This value will be increasing + monotonically. + + Note that although MSRs are per-CPU entities, the effect of this + particular MSR is global. + + Availability of this MSR must be checked via bit 16 in 0x4000001 cpuid + leaf prior to usage.
No functional change; just add documentation for KVM_FEATURE_HOST_SUSPEND_TIME and its corresponding MSR_KVM_HOST_SUSPEND_TIME to support virtual suspend timing injection in later patches. Signed-off-by: Hikaru Nishida <hikalium@chromium.org> --- Documentation/virt/kvm/cpuid.rst | 3 +++ Documentation/virt/kvm/msr.rst | 29 +++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+)