From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM: Fix the invlpg instruction emulation on AMD64 Date: Tue, 16 Oct 2007 11:27:31 +0200 Message-ID: <47148403.6010603@qumranet.com> References: <20071015190823.GA11333@hall.aurel32.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Aurelien Jarno Return-path: In-Reply-To: <20071015190823.GA11333-OqXK5JiLQY5aJl8KAwiEcA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Aurelien Jarno wrote: > The patch below removes the check for c->modrm_reg == 7 to detect the > invlpg instruction, as it was the case before before commit > aa38840d3d2e0a804e628077df8d8879b496d741. This fixes the boot of FreeBSD > on an AMD64 CPU. > > It also moves the assignation of c->src.bytes after the test as it is > not needed for the invlpg instruction. > > Signed-off-by: Aurelien Jarno > > diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c > index fa33fcd..01aa952 100644 > --- a/drivers/kvm/x86_emulate.c > +++ b/drivers/kvm/x86_emulate.c > @@ -824,12 +824,10 @@ modrm_done: > c->src.bytes = 4; > goto srcmem_common; > case SrcMem: > - c->src.bytes = (c->d & ByteOp) ? 1 : > - c->op_bytes; > /* Don't fetch the address for invlpg: it could be unmapped. */ > - if (c->twobyte && c->b == 0x01 > - && c->modrm_reg == 7) > + if (c->twobyte && c->b == 0x01) > break; > + c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes; > > I don't understand why this helps. All of the other instructions in this group either have modrm_mod == 3 or do require evaluation of the source. invlpg is the only one that doesn't. It looks like this patch would break lgdt and lidt (which are only needed on Intel). -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/