KVM: PPC: cache flush for kernel managed pages

Kernel can only access pages which maps as memory.
So flush only the valid kernel pages.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index f58930779ae8..4794de6ea379 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -282,8 +282,15 @@ void kvmppc_init_lpid(unsigned long nr_lpids);
 
 static inline void kvmppc_mmu_flush_icache(pfn_t pfn)
 {
-        /* Clear i-cache for new pages */
         struct page *page;
+        /*
+         * We can only access pages that the kernel maps
+         * as memory. Bail out for unmapped ones.
+         */
+        if (!pfn_valid(pfn))
+                return;
+
+        /* Clear i-cache for new pages */
         page = pfn_to_page(pfn);
         if (!test_bit(PG_arch_1, &page->flags)) {
                 flush_dcache_icache_page(page);