From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753898AbXDVJ2w (ORCPT ); Sun, 22 Apr 2007 05:28:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754052AbXDVJ2w (ORCPT ); Sun, 22 Apr 2007 05:28:52 -0400 Received: from il.qumranet.com ([82.166.9.18]:36211 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754044AbXDVJ2v (ORCPT ); Sun, 22 Apr 2007 05:28:51 -0400 From: Avi Kivity To: stable@kernel.org Cc: linux-kernel@vger.kernel.org, kvm-devel@lists.sourceforge.net, Avi Kivity Subject: [PATCH -stable] KVM: MMU: Fix host memory corruption on i386 with >= 4GB ram Date: Sun, 22 Apr 2007 12:28:49 +0300 Message-Id: <11772341294121-git-send-email-avi@qumranet.com> X-Mailer: git-send-email 1.5.0.6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org PAGE_MASK is an unsigned long, so using it to mask physical addresses on i386 (which are 64-bit wide) leads to truncation. This can result in page->private of unrelated memory pages being modified, with disasterous results. Fix by not using PAGE_MASK for physical addresses; instead calculate the correct value directly from PAGE_SIZE. Also fix a similar BUG_ON(). Acked-by: Ingo Molnar Signed-off-by: Avi Kivity --- drivers/kvm/mmu.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index 1e09d4e..1b5e189 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -131,7 +131,7 @@ static int dbg = 1; (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1)) -#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & PAGE_MASK) +#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)) #define PT64_DIR_BASE_ADDR_MASK \ (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1)) @@ -406,8 +406,8 @@ static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn) spte = desc->shadow_ptes[0]; } BUG_ON(!spte); - BUG_ON((*spte & PT64_BASE_ADDR_MASK) != - page_to_pfn(page) << PAGE_SHIFT); + BUG_ON((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT + != page_to_pfn(page)); BUG_ON(!(*spte & PT_PRESENT_MASK)); BUG_ON(!(*spte & PT_WRITABLE_MASK)); rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); -- 1.5.0.6