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Re: [Xen-devel] [PATCH V6 0/5] x86/hvm: pkeys, add memory protection-key support

On Mon, 2016-01-25 at 08:25 -0700, Jan Beulich wrote:
> > > > On 19.01.16 at 08:30, <huaitong.han@xxxxxxxxx> wrote:
> > Changes in v6:
> > *2 patches merged are not included.
> > *Don't write XSTATE_PKRU to PV's xcr0.
> > *Use "if()" instead of "?:" in cpuid handling patch.
> > *Update read_pkru function.
> > *Use value 4 instead of CONFIG_PAGING_LEVELS.
> > *Add George's patch for PFEC_insn_fetch handling.
> How does this last item match up with ...

"At the moment PFEC_insn_fetch is only set in
hvm_fetch_from_guest_virt() if hvm_nx_enabled() or hvm_smep_enabled()
are true.  Which means that if you *don't* have nx or smep enabled,
then the patch series as is will fault on instruction fetches when it
shouldn't.  (I don't remember anyone mentioning nx or smep being
enabled as a prerequisite for pkeys.)"

I think realistically the only way to address this is to start making
the clean separation between "pfec in" and "pfec out" I mentioned in
the previous discussion.

I've coded up the attached patch, but only compile-tested it.  Can you
give it a look to see if you think it is correct, test it, include it
in your next patch series?

--from George's comments on V5 patches.

> > Huaitong Han (5):
> >   x86/hvm: pkeys, disable pkeys for guests in non-paging mode
> >   x86/hvm: pkeys, add pkeys support for guest_walk_tables
> >   x86/hvm: pkeys, add xstate support for pkeys
> >   xen/mm: Clean up pfec handling in gva_to_gfn
> >   x86/hvm: pkeys, add pkeys support for cpuid handling
> ... all five patches being yours?
I will update a patch author to George.
> Jan
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