[RFC PATCH v3 3/5] kvm/x86: virtual suspend time injection: Add common definitions
From: Hikaru Nishida <hidden>
Date: 2021-10-20 12:05:25
Also in:
kvm, kvmarm, linux-arm-kernel, lkml
Subsystem:
documentation, kernel virtual machine (kvm), kernel virtual machine for x86 (kvm/x86), kvm paravirt (kvm/paravirt), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Jonathan Corbet, Paolo Bonzini, Sean Christopherson, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Add definitions of MSR, KVM_FEATURE bit and a structure called kvm_suspend_time that are used by later patches to support the virtual suspend time injection mechanism. Also add documentations for them. Signed-off-by: Hikaru Nishida <redacted> --- Changes in v3: - Moved the definition of struct kvm_suspend_time into this patch. Documentation/virt/kvm/cpuid.rst | 3 +++ Documentation/virt/kvm/msr.rst | 30 ++++++++++++++++++++++++++++ arch/x86/include/uapi/asm/kvm_para.h | 6 ++++++ 3 files changed, 39 insertions(+)
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst
index bda3e3e737d7..f17b95b0d943 100644
--- a/Documentation/virt/kvm/cpuid.rst
+++ b/Documentation/virt/kvm/cpuid.rst@@ -103,6 +103,9 @@ KVM_FEATURE_HC_MAP_GPA_RANGE 16 guest checks this feature bit bef KVM_FEATURE_MIGRATION_CONTROL 17 guest checks this feature bit before using MSR_KVM_MIGRATION_CONTROL +KVM_FEATURE_HOST_SUSPEND_TIME 18 host suspend time information + is available at msr 0x4b564d09. + 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 9315fc385fb0..40ec0fd263ac 100644
--- a/Documentation/virt/kvm/msr.rst
+++ b/Documentation/virt/kvm/msr.rst@@ -389,3 +389,33 @@ data: guest is communicating page encryption status to the host using the ``KVM_HC_MAP_GPA_RANGE`` hypercall, it can set bit 0 in this MSR to allow live migration of the guest. + +MSR_KVM_HOST_SUSPEND_TIME: + 0x4b564d09 + +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_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 visible to the guest (including TSCs) during + the host's suspension and report the duration of suspend through this + structure. The update will be notified through + HYPERVISOR_CALLBACK_VECTOR IRQ. Fields have the following meanings: + + suspend_time_ns: + Total number of nanoseconds passed during the host's suspend + while the VM is running. This value will be increasing + monotonically and cumulative. + + 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 18 in 0x4000001 cpuid + leaf prior to usage.
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 5146bbab84d4..ccea4e344f46 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h@@ -35,6 +35,7 @@ #define KVM_FEATURE_MSI_EXT_DEST_ID 15 #define KVM_FEATURE_HC_MAP_GPA_RANGE 16 #define KVM_FEATURE_MIGRATION_CONTROL 17 +#define KVM_FEATURE_HOST_SUSPEND_TIME 18 #define KVM_HINTS_REALTIME 0
@@ -57,6 +58,7 @@ #define MSR_KVM_ASYNC_PF_INT 0x4b564d06 #define MSR_KVM_ASYNC_PF_ACK 0x4b564d07 #define MSR_KVM_MIGRATION_CONTROL 0x4b564d08 +#define MSR_KVM_HOST_SUSPEND_TIME 0x4b564d09 struct kvm_steal_time { __u64 steal;
@@ -79,6 +81,10 @@ struct kvm_clock_pairing { __u32 pad[9]; }; +struct kvm_suspend_time { + __u64 suspend_time_ns; +}; + #define KVM_STEAL_ALIGNMENT_BITS 5 #define KVM_STEAL_VALID_BITS ((-1ULL << (KVM_STEAL_ALIGNMENT_BITS + 1))) #define KVM_STEAL_RESERVED_MASK (((1 << KVM_STEAL_ALIGNMENT_BITS) - 1 ) << 1)
--
2.33.0.1079.g6e70778dc9-goog