KVM: arm/arm64: vgic: Avoid flushing vgic state when there's no pending IRQ

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We do not need to flush vgic states in each world switch unless
there is pending IRQ queued to the vgic's ap list. We can thus reduce
the overhead by not grabbing the spinlock and not making the extra
function call to vgic_flush_lr_state.

Note: list_empty is a single atomic read (uses READ_ONCE) and can
therefore check if a list is empty or not without the need to take the
spinlock protecting the list.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Shih-Wei Li <shihwei@cs.columbia.edu>
Signed-off-by: Christoffer Dall <cdall@linaro.org>

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Shih-Wei Li 2016-10-19 18:12:34 +00:00 • committed by Christoffer Dall

parent 328e566479

commit f6769581e9

1 changed files with 17 additions and 0 deletions

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virt/kvm/arm/vgic/vgic.c

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