From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bandan Das Subject: Re: [PATCH] Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS Date: Mon, 05 Oct 2015 13:42:43 -0400 Message-ID: References: <560D1C6E.2060803@suse.com> <560D278F.10801@redhat.com> <20151005095022.GX3036@8bytes.org> <20151005171537.GD12506@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain Cc: Paolo Bonzini , kvm@vger.kernel.org, Dirk =?utf-8?Q?M=C3=BCller?= To: Joerg Roedel Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57269 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750737AbbJERmq (ORCPT ); Mon, 5 Oct 2015 13:42:46 -0400 In-Reply-To: <20151005171537.GD12506@8bytes.org> (Joerg Roedel's message of "Mon, 5 Oct 2015 19:15:37 +0200") Sender: kvm-owner@vger.kernel.org List-ID: Joerg Roedel writes: > On Mon, Oct 05, 2015 at 12:54:43PM -0400, Bandan Das wrote: >> Joerg Roedel writes: >> The problems is that the next_rip field could be stale. If the processor supports >> next_rip, then it will clear it out on the next entry. If it doesn't, >> an old value just sits there (no matter who wrote it) and the problem >> happens when skip_emulated_instruction advances the rip with an incorrect >> value. > > So the right fix would be to just set the guests next_rip to 0 when we > emulate vmrun, just like real hardware does, no? Agreed, resetting to 0 if nrips isn't supported seems right. It would still help having a printk_once in this case IMO :) > > Joerg > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html