Without this patch, kvm cannot start a guest when cpuidle is enabled
if the hardware does not retain cpu state (EL2) in idle state.
This patch re-initailizes EL2 state at CPU_PM_EXIT by calling
kvm_arch_hardware_enable() if and only if kvm has been initialized
before CPU_PM_ENTER, that is, if any vcpus have been created.
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
arch/arm/kvm/arm.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 0871809..fbff638 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -60,6 +60,8 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
static u8 kvm_next_vmid;
static DEFINE_SPINLOCK(kvm_vmid_lock);
+static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
+
static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
{
BUG_ON(preemptible());
@@ -955,12 +957,27 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
unsigned long cmd,
void *v)
{
- if (cmd == CPU_PM_EXIT && kvm_arm_get_running_vcpu()) {
- kvm_arch_hardware_enable();
+ switch (cmd) {
+ case CPU_PM_ENTER:
+ if (__hyp_get_vectors() != hyp_default_vectors)
+ __this_cpu_write(kvm_arm_hardware_enabled, 1);
+ else
+ __this_cpu_write(kvm_arm_hardware_enabled, 0);
+ /*
+ * don't call kvm_arch_hardware_disable() in case of
+ * CPU_PM_ENTER because it does't actually save any state.
+ */
+
+ return NOTIFY_OK;
+ case CPU_PM_EXIT:
+ if (__this_cpu_read(kvm_arm_hardware_enabled))
+ kvm_arch_hardware_enable();
+
return NOTIFY_OK;
- }
- return NOTIFY_DONE;
+ default:
+ return NOTIFY_DONE;
+ }
}
static struct notifier_block hyp_init_cpu_pm_nb = {
--
1.7.9.5
