[PATCH 8/8] KVM: PPC: Add cache flush on page map

[Alexander Graf <agraf@suse.de>]

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 <agraf@suse.de>
---
 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 <asm/kvm_asm.h>
 #include <asm/processor.h>
 #include <asm/page.h>
+#include <asm/cacheflush.h>
 
 #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);
+	}
+}
 
 #endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index baaafde..fbdad0e 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -469,6 +469,7 @@ void flush_dcache_icache_page(struct page *page)
 	__flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
 #endif
 }
+EXPORT_SYMBOL(flush_dcache_icache_page);
 
 void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
 {
-- 
1.6.0.2