Tim Deegan
2008-Dec-09 16:18 UTC
[Xen-devel] [PATCH] Use virtual 8086 mode for VMX guests with CR0.PE == 0
When a VMX guest tries to enter real mode, put it in virtual 8086 mode instead, if that''s possible. Handle all errors and corner cases by falling back to the real-mode emulator. This is similar to the old VMXASSIST system except it uses Xen''s x86_emulate emulator instead of having a partial emulator in the guest firmware. It more than doubles the speed of real-mode operation on VMX. Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Trolle Selander
2008-Dec-10 01:58 UTC
Re: [Xen-devel] [PATCH] Use virtual 8086 mode for VMX guests with CR0.PE == 0
Looks good. I tested it with OS/2 and Win 98, and there''s no regressions in the realmode parts of their bootup, but quite a significant speedup of the boot process in both cases. Cheers, Trolle On Tue, Dec 9, 2008 at 11:18 AM, Tim Deegan <Tim.Deegan@citrix.com> wrote:> When a VMX guest tries to enter real mode, put it in virtual 8086 mode > instead, if that''s possible. Handle all errors and corner cases by > falling back to the real-mode emulator. > > This is similar to the old VMXASSIST system except it uses Xen''s > x86_emulate emulator instead of having a partial emulator in the guest > firmware. It more than doubles the speed of real-mode operation on VMX. > > Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com> > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel