From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH]: KVM: Fix cmpxchg for writeback changes Date: Wed, 25 Jul 2007 12:34:02 +0300 Message-ID: <46A7190A.3080500@qumranet.com> References: <20070725092506.GA19697@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: <20070725092506.GA19697-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: > KVM: Fix writeback for cmpxchg instruction > > The writeback fixes (02c03a326a5df825cc01de426f72e160db2b9538) broke > cmpxchg emulation. The patch below fixes that. > > Signed-off-by: Aurelien Jarno > > diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c > index 21ce977..9d30d10 100644 > --- a/drivers/kvm/x86_emulate.c > +++ b/drivers/kvm/x86_emulate.c > @@ -1275,7 +1275,7 @@ twobyte_insn: > src.val = _regs[VCPU_REGS_RAX]; > emulate_2op_SrcV("cmp", src, dst, _eflags); > /* Always write back. The question is: where to? */ > - d |= Mov; > + no_wb = 0; > if (_eflags & EFLG_ZF) { > /* Success: write back to memory. */ > dst.val = src.orig_val; > > But no_wb defaults to zero? -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- 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/