From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754864AbXDZQ6p (ORCPT ); Thu, 26 Apr 2007 12:58:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754866AbXDZQ6o (ORCPT ); Thu, 26 Apr 2007 12:58:44 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:35001 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754864AbXDZQ62 (ORCPT ); Thu, 26 Apr 2007 12:58:28 -0400 Date: Thu, 26 Apr 2007 09:55:16 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, kvm-devel@lists.sourceforge.net, Avi Kivity , Ingo Molnar Subject: [patch 05/33] KVM: MMU: Fix host memory corruption on i386 with >= 4GB ram Message-ID: <20070426165516.GF1898@kroah.com> References: <20070426165111.393445007@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="kvm-mmu-fix-host-memory-corruption-on-i386-with-4gb-ram.patch" In-Reply-To: <20070426165445.GA1898@kroah.com> User-Agent: Mutt/1.5.15 (2007-04-06) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -stable review patch. If anyone has any objections, please let us know. ------------------ From: Avi Kivity 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 Signed-off-by: Greg Kroah-Hartman --- drivers/kvm/mmu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- 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 kv 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); --