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KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs
authorSean Christopherson <seanjc@google.com>
Wed, 8 Dec 2021 01:52:21 +0000 (01:52 +0000)
committerPaolo Bonzini <pbonzini@redhat.com>
Wed, 19 Jan 2022 17:14:42 +0000 (12:14 -0500)
commit202470d536b2cad22fa859f3e01202571c49ded9
treeaea968b406e49eb94823f86e6a8ccc9ea524149f
parent31f251d4ddfa464c6dd92ee873b9b223e992a085
KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs

Drop the avic_vcpu_is_running() check when waking vCPUs in response to a
VM-Exit due to incomplete IPI delivery.  The check isn't wrong per se, but
it's not 100% accurate in the sense that it doesn't guarantee that the vCPU
was one of the vCPUs that didn't receive the IPI.

The check isn't required for correctness as blocking == !running in this
context.

From a performance perspective, waking a live task is not expensive as the
only moderately costly operation is a locked operation to temporarily
disable preemption.  And if that is indeed a performance issue,
kvm_vcpu_is_blocking() would be a better check than poking into the AVIC.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/x86/kvm/svm/avic.c
arch/x86/kvm/svm/svm.h