KVM: x86: Skip APICv update if APICv is disable at the module level

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Bail from the APICv update paths _before_ taking apicv_update_lock if
APICv is disabled at the module level.  kvm_request_apicv_update() in
particular is invoked from multiple paths that can be reached without
APICv being enabled, e.g. svm_enable_irq_window(), and taking the
rw_sem for write when APICv is disabled may introduce unnecessary
contention and stalls.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211208015236.1616697-25-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2021-12-08 01:52:34 +00:00 • committed by Paolo Bonzini

parent 7446cfebe8

commit f15756428d

2 changed files with 6 additions and 0 deletions

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arch/x86/kvm/hyperv.c

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3

arch/x86/kvm/x86.c

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