Commit 66c768d3 authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: x86: disable preemption while updating apicv inhibition 



Currently nothing prevents preemption in kvm_vcpu_update_apicv.

On SVM, If the preemption happens after we update the
vcpu->arch.apicv_active, the preemption itself will
'update' the inhibition since the AVIC will be first disabled
on vCPU unload and then enabled, when the current task
is loaded again.

Then we will try to update it again, which will lead to a warning
in __avic_vcpu_load, that the AVIC is already enabled.

Fix this by disabling preemption in this code.

Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-6-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 603ccef4

arch/x86/kvm/x86.c

+2 −0
Original line number Diff line number Diff line
@@ -9850,6 +9850,7 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu) 
		return;



	down_read(&vcpu->kvm->arch.apicv_update_lock);

	preempt_disable();



	activate = kvm_vcpu_apicv_activated(vcpu);
@@ -9870,6 +9871,7 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu) 
		kvm_make_request(KVM_REQ_EVENT, vcpu);



out:

	preempt_enable();

	up_read(&vcpu->kvm->arch.apicv_update_lock);

}

EXPORT_SYMBOL_GPL(kvm_vcpu_update_apicv);