From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: KVM: MMU: only write protect mappings at pagetable level Date: Wed, 22 Dec 2010 09:01:57 -0200 Message-ID: <20101222110157.GA4266@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity To: kvm Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63398 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751597Ab0LVLCE (ORCPT ); Wed, 22 Dec 2010 06:02:04 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id oBMB24SI025239 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 22 Dec 2010 06:02:04 -0500 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: If a pagetable contains a writeable large spte, all of its sptes will be write protected, including non-leaf ones, leading to endless pagefaults. Do not write protect pages above PT_PAGE_TABLE_LEVEL, as the spte fault paths assume non-leaf sptes are writable. Signed-off-by: Marcelo Tosatti diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c3853d5..c716ff8 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3442,6 +3442,9 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) if (!test_bit(slot, sp->slot_bitmap)) continue; + if (sp->role.level != PT_PAGE_TABLE_LEVEL) + continue; + pt = sp->spt; for (i = 0; i < PT64_ENT_PER_PAGE; ++i) /* avoid RMW */