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authorMarc Zyngier <marc.zyngier@arm.com>2016-01-29 19:04:48 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2016-02-29 18:34:22 +0000
commit9b4a3004439d5be680faf41f4267968ca11bb9f6 (patch)
tree7d0105f0da12af41b04a23dd4e4f65066d80d6f0 /include/kvm
parentd06a5440a02cf8ff67b1cd4ee75a30b1b1c66cff (diff)
downloadlinux-9b4a3004439d5be680faf41f4267968ca11bb9f6.tar.bz2
KVM: arm/arm64: timer: Add active state caching
Programming the active state in the (re)distributor can be an expensive operation so it makes some sense to try and reduce the number of accesses as much as possible. So far, we program the active state on each VM entry, but there is some opportunity to do less. An obvious solution is to cache the active state in memory, and only program it in the HW when conditions change. But because the HW can also change things under our feet (the active state can transition from 1 to 0 when the guest does an EOI), some precautions have to be taken, which amount to only caching an "inactive" state, and always programing it otherwise. With this in place, we observe a reduction of around 700 cycles on a 2GHz GICv2 platform for a NULL hypercall. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'include/kvm')
-rw-r--r--include/kvm/arm_arch_timer.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 1800227af9d6..b651aed9dc6b 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -55,6 +55,9 @@ struct arch_timer_cpu {
/* VGIC mapping */
struct irq_phys_map *map;
+
+ /* Active IRQ state caching */
+ bool active_cleared_last;
};
int kvm_timer_hyp_init(void);
@@ -74,4 +77,6 @@ bool kvm_timer_should_fire(struct kvm_vcpu *vcpu);
void kvm_timer_schedule(struct kvm_vcpu *vcpu);
void kvm_timer_unschedule(struct kvm_vcpu *vcpu);
+void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);
+
#endif