Re: [PATCH 38/62] x86/sev-es: Handle instruction fetches from user-space

From: Joerg Roedel
Date: Fri Mar 13 2020 - 05:12:27 EST


On Wed, Feb 12, 2020 at 01:42:48PM -0800, Andy Lutomirski wrote:
> I realize that this is a somewhat arbitrary point in the series to
> complain about this, but: the kernel already has infrastructure to
> decode and fix up an instruction-based exception. See
> fixup_umip_exception(). Please refactor code so that you can share
> the same infrastructure rather than creating an entirely new thing.

Okay, but 'infrastructure' is a bold word for the call path down
fixup_umip_exception(). It uses the in-kernel instruction decoder, which
I already use in my patch-set. But I agree that some code in this
patch-set is duplicated and already present in the instruction decoder,
and that fixup_umip_exception() has more robust instruction decoding.

I factor the instruction decoding part out and make is usable for the
#VC handler too and remove the code that is already present in the
instruction decoder.

Regards,

Joerg