9b4a300443
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> |
||
|---|---|---|
| .. | ||
| kvm | ||
| lib | ||
| Makefile | ||