Re: [Xen-devel] PROBLEM: kernel panic xsave_init

[Boris Ostrovsky]

On 10/20/2015 09:43 AM, Jan Beulich wrote:
> > > > On 20.10.15 at 15:22, <boris.ostrovsky@xxxxxxxxxx> wrote:
> > The reason I think its this commit is that RAX, RDX and RCX look very
> > much like arguments to xsetbv (which xstate_enable_boot_cpu() executes)
> > and RAX value is 0x1f, which has two new bits that this commit defined.
> That would be the two MPX related bits, yet us (luckily) white listing
> leaf 7 in pv_cpuid(), it is quite easy to validate that we don't expose
> this feature to PV(H) guests.

Oh, so something like

cpuid=['0x7:ebx=xxxxxxxxxxxxxxxxx0xxxxxxxxxxxxxx']

(bit 14 as zero) for John to try then.


-boris

> Sadly the story is different for HVM
> guests (where the leaf handling uses black listing), but the register
> dump here clearly points to a PV guest (or Dom0).
>
> Jan

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