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| author | Santosh Shukla <santosh.shukla@amd.com> | 2023-02-27 11:40:15 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-03-23 03:43:22 +0300 |
| commit | fa4c027a7956f5e07697bfcb580d25eeb8471257 (patch) | |
| tree | 302abc2013362ae3cb0eb239554d21161311293e /arch/x86/kvm/x86.c | |
| parent | bdedff263132c862924f5cad96f0e82eeeb4e2e6 (diff) | |
| download | linux-fa4c027a7956f5e07697bfcb580d25eeb8471257.tar.xz | |
KVM: x86: Add support for SVM's Virtual NMI
Add support for SVM's Virtual NMIs implementation, which adds proper
tracking of virtual NMI blocking, and an intr_ctrl flag that software can
set to mark a virtual NMI as pending. Pending virtual NMIs are serviced
by hardware if/when virtual NMIs become unblocked, i.e. act more or less
like real NMIs.
Introduce two new kvm_x86_ops callbacks so to support SVM's vNMI, as KVM
needs to treat a pending vNMI as partially injected. Specifically, if
two NMIs (for L1) arrive concurrently in KVM's software model, KVM's ABI
is to inject one and pend the other. Without vNMI, KVM manually tracks
the pending NMI and uses NMI windows to detect when the NMI should be
injected.
With vNMI, the pending NMI is simply stuffed into the VMCB and handed
off to hardware. This means that KVM needs to be able to set a vNMI
pending on-demand, and also query if a vNMI is pending, e.g. to honor the
"at most one NMI pending" rule and to preserve all NMIs across save and
restore.
Warn if KVM attempts to open an NMI window when vNMI is fully enabled,
as the above logic should prevent KVM from ever getting to
kvm_check_and_inject_events() with two NMIs pending _in software_, and
the "at most one NMI pending" logic should prevent having an NMI pending
in hardware and an NMI pending in software if NMIs are also blocked, i.e.
if KVM can't immediately inject the second NMI.
Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20230227084016.3368-11-santosh.shukla@amd.com
[sean: rewrite shortlog and changelog, massage code comments]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index befabb4678f9..f32c2b51c157 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5125,7 +5125,7 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, events->interrupt.shadow = static_call(kvm_x86_get_interrupt_shadow)(vcpu); events->nmi.injected = vcpu->arch.nmi_injected; - events->nmi.pending = vcpu->arch.nmi_pending; + events->nmi.pending = kvm_get_nr_pending_nmis(vcpu); events->nmi.masked = static_call(kvm_x86_get_nmi_mask)(vcpu); /* events->sipi_vector is never valid when reporting to user space */ @@ -10158,13 +10158,31 @@ static void process_nmi(struct kvm_vcpu *vcpu) else limit = 2; + /* + * Adjust the limit to account for pending virtual NMIs, which aren't + * tracked in vcpu->arch.nmi_pending. + */ + if (static_call(kvm_x86_is_vnmi_pending)(vcpu)) + limit--; + vcpu->arch.nmi_pending += atomic_xchg(&vcpu->arch.nmi_queued, 0); vcpu->arch.nmi_pending = min(vcpu->arch.nmi_pending, limit); + if (vcpu->arch.nmi_pending && + (static_call(kvm_x86_set_vnmi_pending)(vcpu))) + vcpu->arch.nmi_pending--; + if (vcpu->arch.nmi_pending) kvm_make_request(KVM_REQ_EVENT, vcpu); } +/* Return total number of NMIs pending injection to the VM */ +int kvm_get_nr_pending_nmis(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.nmi_pending + + static_call(kvm_x86_is_vnmi_pending)(vcpu); +} + void kvm_make_scan_ioapic_request_mask(struct kvm *kvm, unsigned long *vcpu_bitmap) { |