On 03/12/14 21:18, Christoffer Dall wrote: > 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. > > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > --- > Documentation/virtual/kvm/api.txt | 9 +++++++++ > arch/arm/kvm/psci.c | 19 +++++++++++++++++++ > arch/arm64/include/asm/kvm_host.h | 1 + > 3 files changed, 29 insertions(+) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 81f1b97..228f9cf 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -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]; > }; > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index 09cf377..ae0bb91 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/psci.c > @@ -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 +167,24 @@ 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; > + preempt_disable(); > + force_vm_exit(cpu_all_mask); > + preempt_enable(); > + I'm slightly uneasy about this force_vm_exit, as this is something that is directly triggered by the guest. I suppose it is almost impossible to find out which CPUs we're actually using... > 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; > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 65c6152..0b7dfdb 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -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); > Other than that, Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
