From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH] KVM: handle exit due to INVD in VMX Date: Sun, 31 Oct 2010 20:56:51 +0200 Message-ID: <20101031185651.GI2764@redhat.com> References: <20101031143635.GW26191@redhat.com> <30710656-1B22-45B9-AC71-7EB744906A6C@suse.de> <20101031182240.GH2764@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: mtosatti@redhat.com, avi@redhat.com, kvm@vger.kernel.org To: Alexander Graf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53924 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756222Ab0JaS4z (ORCPT ); Sun, 31 Oct 2010 14:56:55 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Oct 31, 2010 at 11:26:09AM -0700, Alexander Graf wrote: > > On 31.10.2010, at 11:22, Gleb Natapov wrote: > > > On Sun, Oct 31, 2010 at 11:00:08AM -0700, Alexander Graf wrote: > >> > >> On 31.10.2010, at 07:36, Gleb Natapov wrote: > >> > >>> Call into emulator when INVD instruction is executed by a guest. > >> > >> Why? This is a poor patch description. > > Why what? Why we need to handle INVD exit instead of stopping with > > unhandled exit error? > > Ah, so we get the exit already, but don't handle it? That's an important piece of information that belongs in the patch description. Another thing I as a reader would also like to know is where this got triggered, so which guests would break without the patch. > I'll add it to the patch description. The guest that triggered it was open firmware, but I do not think this info belongs to patch description too. > I'm also wondering why nobody has seen it before. Is this a regression? Is this exit a side-effect of another feature bit of VMX, so only newer CPUs are affected? > I guess nobody seen it because not many guests use the instruction. Actually this instruction is useful only for firmware use. This is not a regression. -- Gleb.