Re: [kvm-unit-tests PATCH v3 04/11] lib: x86: Import insn decoder from Linux

[Joerg Roedel <jroedel@suse.de>]

Hi,

trying to get some tracktion here again.

On Wed, Apr 06, 2022 at 01:37:02AM +0000, Sean Christopherson wrote:
> Do we really need Linux's decoder for this?  Linux needs a more robust decoder
> because it has to deal with userspace crud, but KUT should have full control over
> what code it encounters in a #VC handler, e.g. we should never have to worry about
> ignore prefixes on a WRMSR.  And looking at future patches, KUT is still looking
> at raw opcode bytes, e.g.

I think just importing Linux' instruction decoder is the most robust
solution for kvm-unit-tests. The code does MMIO today and who knows what
the future will bring. To minimize the risk that changes unrelated to
SEV-ES will break it all the time, having a full instruction decoder is
the best option.

The maintenance cost for this should be pretty low, as the Linux code
has no dependencies and new versions can be ported over as needed with
little effort.

Regards,

-- 
Jörg Rödel
jroedel@suse.de

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