On Wed, Aug 14, 2013 at 7:53 PM, Sudeep KarkadaNagesha Sudeep.KarkadaNagesha@arm.com wrote:
On 14/08/13 12:47, Pranavkumar Sawargaonkar wrote:
Systems with large external L3-cache (few MBs), might have dirty content belonging to the guest page in L3-cache. To tackle this, we need to flush such dirty content from d-cache so that guest will see correct contents of guest page when guest MMU is disabled.
The patch fixes coherent_icache_guest_page() for external L3-cache.
I don't understand KVM but the commit message caught my attention.
You are referring to clean the external/outer L3 cache but using internal cache maintenance APIs. You should be using outer_cache APIs if you really intend to do outer cache maintenance ? Is the external/outer L3 cache not unified ?
Or did you mean to flush d-cache to the point of coherency(external L3 in your case)? If so it's not clear from the commit log.
Yes, we mean to flush d-cache to the point of coherency (which in our case is external L3-cache).
The patch description is more in-terms of KVM virtualization but, we can certainly add more details.
Regards, Sudeep
Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org Signed-off-by: Anup Patel anup.patel@linaro.org
arch/arm64/include/asm/kvm_mmu.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index efe609c..5129038 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -123,6 +123,8 @@ static inline void coherent_icache_guest_page(struct kvm *kvm, gfn_t gfn) if (!icache_is_aliasing()) { /* PIPT */ unsigned long hva = gfn_to_hva(kvm, gfn); flush_icache_range(hva, hva + PAGE_SIZE);
/* Flush d-cache for systems with external caches. */__flush_dcache_area((void *) hva, PAGE_SIZE); } else if (!icache_is_aivivt()) { /* non ASID-tagged VIVT */ /* any kind of VIPT cache */ __flush_icache_all();
linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Regards, Anup