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

[Christoph Egger <Christoph.Egger@xxxxxxx>]

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>


-- 
---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

xen_pae.diff
Description: Text Data

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