path: root/arch/arm/include
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authorChristoffer Dall <christoffer.dall@linaro.org>2015-08-25 19:48:21 +0200
committerChristoffer Dall <christoffer.dall@linaro.org>2015-10-22 23:01:42 +0200
commitd35268da66870d733ae763fd7f9b06a1f63f395e (patch)
tree408e3ad5ebdc30184c149c065aea29d0bc066f07 /arch/arm/include
parent3217f7c25bca66eed9b07f0b8bfd1937169b0736 (diff)
arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_block
We currently schedule a soft timer every time we exit the guest if the timer did not expire while running the guest. This is really not necessary, because the only work we do in the timer work function is to kick the vcpu. Kicking the vcpu does two things: (1) If the vpcu thread is on a waitqueue, make it runnable and remove it from the waitqueue. (2) If the vcpu is running on a different physical CPU from the one doing the kick, it sends a reschedule IPI. The second case cannot happen, because the soft timer is only ever scheduled when the vcpu is not running. The first case is only relevant when the vcpu thread is on a waitqueue, which is only the case when the vcpu thread has called kvm_vcpu_block(). Therefore, we only need to make sure a timer is scheduled for kvm_vcpu_block(), which we do by encapsulating all calls to kvm_vcpu_block() with kvm_timer_{un}schedule calls. Additionally, we only schedule a soft timer if the timer is enabled and unmasked, since it is useless otherwise. Note that theoretically userspace can use the SET_ONE_REG interface to change registers that should cause the timer to fire, even if the vcpu is blocked without a scheduled timer, but this case was not supported before this patch and we leave it for future work for now. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm/include')
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 84da97901f1f..c4072d9f32c7 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -234,7 +234,4 @@ static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}
-static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
-static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
#endif /* __ARM_KVM_HOST_H__ */