Re: [PATCH 2/2] tpm: add backend for mssim

[Daniel P . Berrangé]

On Thu, Dec 15, 2022 at 03:53:43PM -0500, Stefan Berger wrote:
> 
> 
> On 12/15/22 15:30, James Bottomley wrote:
> > On Thu, 2022-12-15 at 15:22 -0500, Stefan Berger wrote:
> > > On 12/15/22 15:07, James Bottomley wrote:
> > [...]
> > > > don't really have much interest in the migration use case, but I
> > > > knew it should work like the passthrough case, so that's what I
> > > > tested.
> > > 
> > > I think your device needs to block migrations since it doesn't handle
> > > all migration scenarios correctly.
> > 
> > Passthrough doesn't block migrations either, presumably because it can
> > also be made to work if you know what you're doing.  I might not be
> 
> Don't compare it to passthrough, compare it to swtpm. It should
> have at least the same features as swtpm or be better, otherwise
> I don't see why we need to have the backend device in the upstream
> repo.

James has explained multiple times that mssim is a beneficial
thing to support, given that it is the reference implementation
of TPM2. Requiring the same or greater features than swtpm is
an unreasonable thing to demand.

With regards,
Daniel
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