To avoid a race between turning VCPUs off and turning them on, make sure
that only the VCPU threat itself turns off the VCPU. When other threads
want to turn of a VCPU, they now do this via a request.
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm/include/asm/kvm_host.h | 2 ++
arch/arm64/include/asm/kvm_host.h | 2 ++
virt/kvm/arm/arm.c | 8 ++++++--
virt/kvm/arm/psci.c | 11 ++---------
4 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 50e89869178a..b1cfae222441 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -49,6 +49,8 @@
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2)
+#define KVM_REQ_VCPU_OFF \
+ KVM_ARCH_REQ_FLAGS(3, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index da3fc7324d68..d43b13421987 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -49,6 +49,8 @@
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1)
#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2)
+#define KVM_REQ_VCPU_OFF \
+ KVM_ARCH_REQ_FLAGS(3, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 9c486fad3f9f..785076176814 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -404,8 +404,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
static void vcpu_power_off(struct kvm_vcpu *vcpu)
{
- vcpu->arch.power_off = true;
- kvm_make_request(KVM_REQ_SLEEP, vcpu);
+ kvm_make_request(KVM_REQ_VCPU_OFF, vcpu);
kvm_vcpu_kick(vcpu);
}
@@ -646,6 +645,11 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
if (kvm_check_request(KVM_REQ_SLEEP, vcpu))
vcpu_req_sleep(vcpu);
+ if (kvm_check_request(KVM_REQ_VCPU_OFF, vcpu)) {
+ vcpu->arch.power_off = true;
+ vcpu_req_sleep(vcpu);
+ }
+
if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
kvm_reset_vcpu(vcpu);
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index b9cff1d4b06d..20255319e193 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -97,9 +97,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
{
- vcpu->arch.power_off = true;
- kvm_make_request(KVM_REQ_SLEEP, vcpu);
- kvm_vcpu_kick(vcpu);
+ kvm_make_request(KVM_REQ_VCPU_OFF, vcpu);
}
static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
@@ -198,9 +196,6 @@ 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
@@ -210,9 +205,7 @@ 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)
- tmp->arch.power_off = true;
- kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
+ kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_VCPU_OFF);
memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
vcpu->run->system_event.type = type;
--
2.18.0
