Re: [PATCH] x86: correctly initialize the CS base on reset

From: Gleb Natapov
Date: Tue Mar 19 2013 - 13:08:06 EST

On Tue, Mar 19, 2013 at 05:41:45PM +0100, Jan Kiszka wrote:
> On 2013-03-19 16:43, Gleb Natapov wrote:
> > On Tue, Mar 19, 2013 at 04:30:26PM +0100, Paolo Bonzini wrote:
> >> The CS base was initialized to 0 on VMX (wrong, but usually overridden
> >> by userspace before starting) or 0xf0000 on SVM. The correct value is
> >> 0xffff0000, and VMX is able to emulate it now, so use it.
> >>
> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Reviewed-by: Gleb Natapov <gleb@xxxxxxxxxx>
> Just for the history (as I was wondering where this came from): CS base
> used to be set to 0xf0000 on VMX as well, but that was changed by
> b246dd5d to only affect guests when unrestricted mode is missing. That
> change actually left the base uninitialized.
Looking at the code before b246dd5d it sets CS base to 0xf0000 only if it was
0xffff0000. This is the same as with current code: fix_rmode_seg() does

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