Re: [PATCH] x86: Always have CR4.PKE set in HVM context

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.04.2021 16:37, Andrew Cooper wrote:
> On 30/04/2021 11:42, Jan Beulich wrote:
>> On 30.04.2021 12:21, Andrew Cooper wrote:
>>> If I do the rebase, are you happy for this patch to stay as it is (so
>>> the complicated change concerning context switching doesn't get more
>>> complicated), and so we're not knowingly adding new constructs which
>>> need immediate changes?
>> Well, the answer is not just "yes", but in reality I wouldn't mind
>> doing the rebasing myself, if only I knew it wasn't for the purpose of
>> waiting another half year for an ack (or otherwise).
> 
> The patch itself looks entirely fine.  Reviewed-by: Andrew Cooper
> <andrew.cooper3@xxxxxxxxxx>

Thanks.

> The only observation I've got is that the other instructions in Grp7
> probably want a blanket conversion from generate_exception_if(vex.pfx,
> EXC_UD); to use the unimplemented_insn path instead, but that's clearly
> further work.

Since this is highly inconsistent at present, we first need to put
down a scheme, as I don't think we want _all_ #UD raising converted
to "goto unimplemented_insn". I've been thinking about where to draw
the line every time I've been adding new insns half-way recently,
but I didn't come to any good conclusion yet.

> I'll commit this patch, and the rebase delta on yours ought to just be
> the naming of the helpers.

Plus the dropping of the CR4 writes in write_pkru().

Jan