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Commit cf5d3188 authored by Christoffer Dall's avatar Christoffer Dall
Browse files

arm/arm64: KVM: Turn off vcpus on PSCI shutdown/reboot 



When a vcpu calls SYSTEM_OFF or SYSTEM_RESET with PSCI v0.2, the vcpus
should really be turned off for the VM adhering to the suggestions in
the PSCI spec, and it's the sane thing to do.

Also, clarify the behavior and expectations for exits to user space with
the KVM_EXIT_SYSTEM_EVENT case.

Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent f7fa034d

Documentation/virtual/kvm/api.txt

+9 −0
Original line number Diff line number Diff line
@@ -2957,6 +2957,15 @@ HVC instruction based PSCI call from the vcpu. The 'type' field describes 
the system-level event type. The 'flags' field describes architecture

specific flags for the system-level event.



Valid values for 'type' are:

  KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the

   VM. Userspace is not obliged to honour this, and if it does honour

   this does not need to destroy the VM synchronously (ie it may call

   KVM_RUN again before shutdown finally occurs).

  KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM.

   As with SHUTDOWN, userspace can choose to ignore the request, or

   to schedule the reset to occur in the future and may call KVM_RUN again.



		/* Fix the size of the union. */

		char padding[256];

	};

arch/arm/kvm/psci.c

+18 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/preempt.h>

#include <linux/kvm_host.h>

#include <linux/wait.h>
@@ -166,6 +167,23 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) 


static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)

{

	int i;

	struct kvm_vcpu *tmp;



	/*

	 * The KVM ABI specifies that a system event exit may call KVM_RUN

	 * again and may perform shutdown/reboot at a later time that when the

	 * actual request is made.  Since we are implementing PSCI and a

	 * caller of PSCI reboot and shutdown expects that the system shuts

	 * down or reboots immediately, let's make sure that VCPUs are not run

	 * after this call is handled and before the VCPUs have been

	 * re-initialized.

	 */

	kvm_for_each_vcpu(i, tmp, vcpu->kvm) {

		tmp->arch.pause = true;

		kvm_vcpu_kick(tmp);

	}



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

	vcpu->run->system_event.type = type;

	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;

arch/arm64/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void); 
struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);



u64 kvm_call_hyp(void *hypfn, ...);

void force_vm_exit(const cpumask_t *mask);



int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,

		int exception_index);