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| author |   Maxim Levitsky <mlevitsk@redhat.com> | 2022-02-08 06:45:16 -0500 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2022-02-11 12:53:02 -0500 |
| commit | 0a5f784273aad41a22963fc8b818ead3c892c97a (patch) | |
| tree | 66baea5ff86dbc70fbf1649b3753320ff9ca2e72 /arch | |
| parent | selftests: kvm: Remove absent target file (diff) | |
| download | linux-dev-0a5f784273aad41a22963fc8b818ead3c892c97a.tar.xz linux-dev-0a5f784273aad41a22963fc8b818ead3c892c97a.zip | |
KVM: SVM: extract avic_ring_doorbell
The check on the current CPU adds an extra level of indentation to
svm_deliver_avic_intr and conflates documentation on what happens
if the vCPU exits (of interest to svm_deliver_avic_intr) and migrates
(only of interest to avic_ring_doorbell, which calls get/put_cpu()).
Extract the wrmsr to a separate function and rewrite the
comment in svm_deliver_avic_intr().
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/svm/avic.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 3f9b48732aea..242cb220893a 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -269,6 +269,22 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) return 0; } +static void avic_ring_doorbell(struct kvm_vcpu *vcpu) +{ + /* + * Note, the vCPU could get migrated to a different pCPU at any point, + * which could result in signalling the wrong/previous pCPU. But if + * that happens the vCPU is guaranteed to do a VMRUN (after being + * migrated) and thus will process pending interrupts, i.e. a doorbell + * is not needed (and the spurious one is harmless). + */ + int cpu = READ_ONCE(vcpu->cpu); + + if (cpu != get_cpu()) + wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu)); + put_cpu(); +} + static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source, u32 icrl, u32 icrh) { @@ -669,19 +685,12 @@ int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec) * automatically process AVIC interrupts at VMRUN. */ if (vcpu->mode == IN_GUEST_MODE) { - int cpu = READ_ONCE(vcpu->cpu); - /* - * Note, the vCPU could get migrated to a different pCPU at any - * point, which could result in signalling the wrong/previous - * pCPU. But if that happens the vCPU is guaranteed to do a - * VMRUN (after being migrated) and thus will process pending - * interrupts, i.e. a doorbell is not needed (and the spurious - * one is harmless). + * Signal the doorbell to tell hardware to inject the IRQ. If + * the vCPU exits the guest before the doorbell chimes, hardware + * will automatically process AVIC interrupts at the next VMRUN. */ - if (cpu != get_cpu()) - wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu)); - put_cpu(); + avic_ring_doorbell(vcpu); } else { /* * Wake the vCPU if it was blocking. KVM will then detect the |