Commit cc9b43f9 authored Jun 04, 2017 by Andrew Jones Committed by Christoffer Dall Jun 04, 2017

KVM: arm/arm64: use vcpu requests for power_off



System shutdown is currently using request-less VCPU kicks. This
leaves open a tiny race window, as it doesn't ensure the state
change to power_off is seen by a VCPU just about to enter guest
mode. VCPU requests, OTOH, are guaranteed to be seen (see "Ensuring
Requests Are Seen" of Documentation/virtual/kvm/vcpu-requests.rst)
This patch applies the EXIT request used by pause to power_off,
fixing the race.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>

parent 0592c005

virt/kvm/arm/psci.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -179,10 +179,9 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
		* after this call is handled and before the VCPUs have been
		* re-initialized.
		*/
		kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
		kvm_for_each_vcpu(i, tmp, vcpu->kvm)
		tmp->arch.power_off = true;
		kvm_vcpu_kick(tmp);
		}
		kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_VCPU_EXIT);

		memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
		vcpu->run->system_event.type = type;