[PATCH] ARM64: KVM: Fix coherent_icache_guest_page() for host with external L3-cache.

Marc Zyngier marc.zyngier at arm.com
Fri Aug 30 10:22:11 EDT 2013

On 2013-08-30 15:04, Catalin Marinas wrote:
> On Fri, Aug 30, 2013 at 02:21:57PM +0100, Marc Zyngier wrote:
>> On 2013-08-30 11:44, Anup Patel wrote:
>> > For KVM, we can avoid flushing d-cache to PoC every time in
>> > coherent_icache_guest_page() by only doing it when Guest MMU is
>> > turned-off. This may reduce the performance penalty.
>> What about the I and C bits in SCTLR_EL1? Does L3 also honour these
>> bits?
> I would think so, it probably cares about how the transactions are
> presented at the bus level by the CPU.

That'd make sense indeed. So we need to track both SCTLR_EL1.{I,C,M} in 
order to find out whether or not we need to clean the cache.

Mumble mumble...

Fast, cheap, reliable. Pick two.

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