KVM: arm/arm64: Simplify bg_timer programming

Instead of calling into kvm_timer_[un]schedule from the main kvm
blocking path, test if the VCPU is on the wait queue from the load/put
path and perform the background timer setup/cancel in this path.

This has the distinct advantage that we no longer race between load/put
and schedule/unschedule and programming and canceling of the bg_timer
always happens when the timer state is not loaded.

Note that we must now remove the checks in kvm_timer_blocking that do
not schedule a background timer if one of the timers can fire, because
we no longer have a guarantee that kvm_vcpu_check_block() will be called
before kvm_timer_blocking.

Reported-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Christoffer Dall
2018-11-26 18:21:22 +01:00
committed by Marc Zyngier
parent e329fb75d5
commit accb99bcd0
3 changed files with 14 additions and 26 deletions

View File

@@ -76,9 +76,6 @@ int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
bool kvm_timer_is_pending(struct kvm_vcpu *vcpu);
void kvm_timer_schedule(struct kvm_vcpu *vcpu);
void kvm_timer_unschedule(struct kvm_vcpu *vcpu);
u64 kvm_phys_timer_read(void);
void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu);