From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH 8/8] KVM: PPC: Add cache flush on page map Date: Tue, 7 Aug 2012 16:01:21 -0500 Message-ID: <50218221.1000609@freescale.com> References: <1344337036-22244-1-git-send-email-agraf@suse.de> <1344337036-22244-9-git-send-email-agraf@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , KVM list To: Alexander Graf Return-path: In-Reply-To: <1344337036-22244-9-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 08/07/2012 05:57 AM, Alexander Graf wrote: > When we map a page that wasn't icache cleared before, do so when first > mapping it in KVM using the same information bits as the Linux mapping > logic. That way we are 100% sure that any page we map does not have stale > entries in the icache. > > What we really would need is a method to flush the icache only when we > actually map a page executable for the guest. But with the current > abstraction that is hard to do, and this way we don't have a huge performance > penalty, so better be safe now and micro optimize things later. > > Signed-off-by: Alexander Graf > --- > arch/powerpc/include/asm/kvm_host.h | 10 ++++++++++ > arch/powerpc/mm/mem.c | 1 + > 2 files changed, 11 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index ed75bc9..c0a2fc1 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -33,6 +33,7 @@ > #include > #include > #include > +#include > > #define KVM_MAX_VCPUS NR_CPUS > #define KVM_MAX_VCORES NR_CPUS > @@ -550,5 +551,14 @@ struct kvm_vcpu_arch { > #define KVM_MMIO_REG_FQPR 0x0060 > > #define __KVM_HAVE_ARCH_WQP > +#define __KVM_HAVE_ARCH_MAP_PAGE > +static inline void kvm_arch_map_page(struct page *page) > +{ > + /* Need to invalidate the icache for new pages */ > + if (!test_bit(PG_arch_1, &page->flags)) { > + flush_dcache_icache_page(page); > + set_bit(PG_arch_1, &page->flags); > + } > +} Shouldn't this test CPU_FTR_COHERENT_ICACHE? -Scott