Xen devel - Jun 2008 - [PATCH] [HVM] Fix lmsw handling

The lmsw instruction can be used to set CR0_PE, but can never clear it, once
set. Currently, as far as I can see, there is no provision to keep lmsw from
clearing CR0_PE, either in the vmx code or in x86_emulate code (which is
used by SVM to emulate lmsw). This patch fixes this issue.

Signed-off-by: Trolle Selander <trolle.selander@eu.citrix.com>



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

I applied it, but then realised that additionally LMSW can only affect bits
0-3 of CR0. Additionally SMSW emulation is wrong because it is only limited
to 16-bit operation when the destination operand is memory. So I¹ve fixed up
these things in a subsequent changeset.

 -- Keir

On 27/6/08 14:11, "Trolle Selander" <trolle.selander@gmail.com>
wrote:
> The lmsw instruction can be used to set CR0_PE, but can never clear it,
once
> set. Currently, as far as I can see, there is no provision to keep lmsw
from
> clearing CR0_PE, either in the vmx code or in x86_emulate code (which is
used
> by SVM to emulate lmsw). This patch fixes this issue.
> 
> Signed-off-by: Trolle Selander <trolle.selander@eu.citrix.com>
> 



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel