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KVM: x86: check for interrupts before deciding whether to exit the fast path

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The kvm_x86_sync_pir_to_irr callback can sometimes set KVM_REQ_EVENT.
If that happens exactly at the time that an exit is handled as
EXIT_FASTPATH_REENTER_GUEST, vcpu_enter_guest will go incorrectly
through the loop that calls kvm_x86_run, instead of processing
the request promptly.

Fixes: 379a3c8ee444 ("KVM: VMX: Optimize posted-interrupt delivery for timer fastpath")
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2021-10-20 06:27:36 -04:00
parent 9f1ee7b169
commit de7cd3f676
1 changed files with 5 additions and 5 deletions
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10
arch/x86/kvm/x86.c
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@ -9643,14 +9643,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST))
break;
if (unlikely(kvm_vcpu_exit_request(vcpu))) {
if (vcpu->arch.apicv_active)
static_call(kvm_x86_sync_pir_to_irr)(vcpu);
if (unlikely(kvm_vcpu_exit_request(vcpu))) {
exit_fastpath = EXIT_FASTPATH_EXIT_HANDLED;
break;
}
if (vcpu->arch.apicv_active)
static_call(kvm_x86_sync_pir_to_irr)(vcpu);
}
}
/*
* Do this here before restoring debug registers on the host. And