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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: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
hifive-unleashed-5.1
Christoffer Dall 2014-10-16 17:00:18 +02:00
parent f7fa034dc8
commit cf5d318865
3 changed files with 28 additions and 0 deletions
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9
Documentation/virtual/kvm/api.txt
View File

@ -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];
};

18
arch/arm/kvm/psci.c
View File

@ -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;

1
arch/arm64/include/asm/kvm_host.h
View File

@ -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);