Re: [Xen-devel] [PATCH] [SVM]: Make 32bit legacy guests boot again

[Christoph Egger <Christoph.Egger@xxxxxxx>]

Your changes broke the boot of 64bit guests. I see a triple fault now.

Christoph


On Monday 29 June 2009 11:17:39 Keir Fraser wrote:
> I forgot to push. Should be there now.
>
>   -- Keir
>
> On 29/06/2009 09:39, "Christoph Egger" <Christoph.Egger@xxxxxxx> wrote:
> > 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" <Christoph.Egger@xxxxxxx> 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 <Christoph.Egger@xxxxxxx>



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