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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2020-05-25 16:41:22 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-01 10:26:08 +0200 |
| commit | 72de5fa4c16195827252b961ba44028a39dfeaff (patch) | |
| tree | e662fd0440ec378bd99ce131cee9b51f08bb0863 /Documentation/virt | |
| parent | KVM: x86: acknowledgment mechanism for async pf page ready notifications (diff) | |
| download | linux-72de5fa4c16195827252b961ba44028a39dfeaff.tar.xz linux-72de5fa4c16195827252b961ba44028a39dfeaff.zip | |
KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT
Introduce new capability to indicate that KVM supports interrupt based
delivery of 'page ready' APF events. This includes support for both
MSR_KVM_ASYNC_PF_INT and MSR_KVM_ASYNC_PF_ACK.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200525144125.143875-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/cpuid.rst | 6 | ||||
| -rw-r--r-- | Documentation/virt/kvm/msr.rst | 12 |
2 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst index f721c89327ec..a7dff9186bed 100644 --- a/Documentation/virt/kvm/cpuid.rst +++ b/Documentation/virt/kvm/cpuid.rst @@ -86,6 +86,12 @@ KVM_FEATURE_PV_SCHED_YIELD 13 guest checks this feature bit before using paravirtualized sched yield. +KVM_FEATURE_ASYNC_PF_INT 14 guest checks this feature bit + before using the second async + pf control msr 0x4b564d06 and + async pf acknowledgment msr + 0x4b564d07. + KVM_FEATURE_CLOCSOURCE_STABLE_BIT 24 host will warn if no guest-side per-cpu warps are expeced in kvmclock diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst index 9b107889b033..e37a14c323d2 100644 --- a/Documentation/virt/kvm/msr.rst +++ b/Documentation/virt/kvm/msr.rst @@ -213,7 +213,8 @@ data: cpl == 0. Bit 2 is 1 if asynchronous page faults are delivered to L1 as #PF vmexits. Bit 2 can be set only if KVM_FEATURE_ASYNC_PF_VMEXIT is present in CPUID. Bit 3 enables interrupt based delivery of 'page ready' - events. + events. Bit 3 can only be set if KVM_FEATURE_ASYNC_PF_INT is present in + CPUID. 'Page not present' events are currently always delivered as synthetic #PF exception. During delivery of these events APF CR2 register contains @@ -242,7 +243,8 @@ data: Note, MSR_KVM_ASYNC_PF_INT MSR specifying the interrupt vector for 'page ready' APF delivery needs to be written to before enabling APF mechanism - in MSR_KVM_ASYNC_PF_EN or interrupt #0 can get injected. + in MSR_KVM_ASYNC_PF_EN or interrupt #0 can get injected. The MSR is + available if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. Note, previously, 'page ready' events were delivered via the same #PF exception as 'page not present' events but this is now deprecated. If @@ -360,7 +362,8 @@ data: Interrupt vector for asynchnonous 'page ready' notifications delivery. The vector has to be set up before asynchronous page fault mechanism - is enabled in MSR_KVM_ASYNC_PF_EN. + is enabled in MSR_KVM_ASYNC_PF_EN. The MSR is only available if + KVM_FEATURE_ASYNC_PF_INT is present in CPUID. MSR_KVM_ASYNC_PF_ACK: 0x4b564d07 @@ -371,4 +374,5 @@ data: When the guest is done processing 'page ready' APF event and 'token' field in 'struct kvm_vcpu_pv_apf_data' is cleared it is supposed to 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. + and check if there are more notifications pending. The MSR is available + if KVM_FEATURE_ASYNC_PF_INT is present in CPUID. |