From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] kvm/fpu: Enable fully eager restore kvm FPU Date: Mon, 20 Aug 2012 13:08:14 +0300 Message-ID: <50320C8E.6040109@redhat.com> References: <1345094044-28962-1-git-send-email-xudong.hao@intel.com> <502CB881.1040807@redhat.com> <403610A45A2B5242BD291EDAE8B37D300FE8AA17@SHSMSX102.ccr.corp.intel.com> <502CD276.7020403@redhat.com> <20120820092416.GB2582@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Hao, Xudong" , "kvm@vger.kernel.org" , "Zhang, Xiantao" To: "Roedel, Joerg" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51845 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751333Ab2HTKIY (ORCPT ); Mon, 20 Aug 2012 06:08:24 -0400 In-Reply-To: <20120820092416.GB2582@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/20/2012 12:24 PM, Roedel, Joerg wrote: > (Back from vacation) > > On Thu, Aug 16, 2012 at 01:59:02PM +0300, Avi Kivity wrote: >> Ok. Please check that ~KVM_XSTATE_LAZY expands to 64-bits correctly, >> maybe we need to cast it to u64 before negating it. >> >> Note that we limit xcr0 to the bits allowed by the host, so the currect >> kernel is safe even on hardware with state that isn't tracked by cr0.ts. >> But it's better to be safe here. >> >> Joerg, IIRC LWP uses one of these bits? Should it be added to the mask? > > LWP uses bit 62 in xcr0 and is not tracked by cr0.ts either. So this bit > should be used to the mask too (in other words LWP is a non-lazy state). So it was broken all along? Yikes. -- error compiling committee.c: too many arguments to function