Re: [Xen-devel] [PATCH 2 of 2] [v3] xen/x86: Add FS and GS base to HVM VCPU context

[Aravindh Puthiyaparambil <aravindh@xxxxxxxxxxxx>]

On Apr 27, 2012 8:02 AM, "Keir Fraser" <keir@xxxxxxx> wrote:
>
> On 27/04/2012 13:49, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>
> >>>> On 25.04.12 at 20:38, Aravindh Puthiyaparambil <aravindh@xxxxxxxxxxxx>
> >>>> wrote:
> >> Add FS and GS base to the HVM VCPU context returned by xc_vcpu_getcontext()
> >
> > Given that we're in feature freeze right now - is this actually fixing some
> > shortcoming somewhere? Otherwise it may need to wait until 4.2 is out.
>
> I think we can make a judgement call on this one that it is obviously safe
> to check it in. Even if the patch is buggy, it's only filling in data fields
> with garbage, which were uninitialised garbage in the first place.
>

It will be helpful if this can make it into 4.2. It does provide useful info for Windows guests.

Thanks,
Aravindh

>  -- Keir
>
> > Jan
> >
> >> Signed-off-by: Aravindh Puthiyaparambil <aravindh@xxxxxxxxxxxx>
> >>
> >> diff -r be41f3b599d9 -r 1f39b9fe704f xen/arch/x86/domctl.c
> >> --- a/xen/arch/x86/domctl.c Wed Apr 25 11:35:29 2012 -0700
> >> +++ b/xen/arch/x86/domctl.c Wed Apr 25 11:35:43 2012 -0700
> >> @@ -1590,8 +1590,23 @@ void arch_get_info_guest(struct vcpu *v,
> >>          c.nat->user_regs.es = sreg.sel;
> >>          hvm_get_segment_register(v, x86_seg_fs, &sreg);
> >>          c.nat->user_regs.fs = sreg.sel;
> >> +#ifdef __x86_64__
> >> +        c.nat->fs_base = sreg.base;
> >> +#endif
> >>          hvm_get_segment_register(v, x86_seg_gs, &sreg);
> >>          c.nat->user_regs.gs = sreg.sel;
> >> +#ifdef __x86_64__
> >> +        if ( ring_0(&c.nat->user_regs) )
> >> +        {
> >> +            c.nat->gs_base_kernel = sreg.base;
> >> +            c.nat->gs_base_user = hvm_get_shadow_gs_base(v);
> >> +        }
> >> +        else
> >> +        {
> >> +            c.nat->gs_base_user = sreg.base;
> >> +            c.nat->gs_base_kernel = hvm_get_shadow_gs_base(v);
> >> +        }
> >> +#endif
> >>      }
> >>      else
> >>      {
> >
> >
> >
>
>

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