From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Egger Subject: Re: [PATCH] [SVM]: Make 32bit legacy guests boot again Date: Mon, 29 Jun 2009 10:39:59 +0200 Message-ID: <200906291040.00326.Christoph.Egger@amd.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Tnx. I will check as soon as it appears in the public staging tree. Christoph On Saturday 27 June 2009 11:35:20 Keir Fraser wrote: > Changeset 19856 is a cleaned up and streamlined version of this patch. > Please take a look. It also fixes a couple of largely theoretical issues: > * Should depend on EFER.LMA not EFER.LME > * Should handle the LMA 1->0 transition (i.e., return to legacy mode). > > -- Keir > > On 26/06/2009 16:19, "Christoph Egger" wrote: > > Hi! > > > > Attached patch fixes a bug introduced in c/s 19648. > > > > 32bit legacy guests have the sysenter/sysexit instructions available. > > Therefore, we have to disable intercepts for the sysenter MSRs or the > > guest stucks in an infinite loop of #GPs, otherwise. > > > > For guests in 64bit mode and 32bit compat mode, sysenter/sysexit > > instructions aren't available. The sysenter MSRs have to be intercepted > > to make the instruction emulation working. > > > > Attach patch first assumes the guest is in 32bit legacy mode and > > therefore disables the sysenter MSRs in construct_vmcb(). > > Access to the MSR_EFER is intercepted. When the guest enables longmode, > > then enable interception of the sysenter MSRs. > > > > Signed-off-by: Christoph Egger -- ---to satisfy European Law for business letters: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen Geschaeftsfuehrer: Thomas M. McCoy, Giuliano Meroni Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632