Re: [kvm-unit-tests PATCH v2 0/1] s390x: do not enable PV dump support by default

From: Nico Boehr <nrb@linux.ibm.com>
To: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: kvm@vger.kernel.org, frankja@linux.ibm.com, thuth@redhat.com
Subject: Re: [kvm-unit-tests PATCH v2 0/1] s390x: do not enable PV dump support by default
Date: Wed, 19 Oct 2022 17:24:16 +0200	[thread overview]
Message-ID: <166619305695.37435.2798515077166987872@t14-nrb> (raw)
In-Reply-To: <20221019171920.455451ea@p-imbrenda>

Quoting Claudio Imbrenda (2022-10-19 17:19:43)
> On Wed, 19 Oct 2022 16:53:19 +0200
> Nico Boehr <nrb@linux.ibm.com> wrote:
> 
> > v1->v2:
> > ---
> > * add indent to CONFIG_DUMP if in Makefile (thanks Janosch)
> > * add comment (thanks Janosch)
> > 
> > Currently, dump support is always enabled by setting the respective
> > plaintext control flag (PCF). Unfortunately, older machines without
> > support for PV dump will not start the guest when this PCF is set.
> 
> maybe for the long term we could try to fix the stub generated by
> genprotimg to check the plaintext flags and the available features and
> refuse to try to start if the required features are missing.
> 
> ideally providing a custom message when generating the image, to be
> shown if the required features are missing. e.g. for kvm unit test, the
> custom message could be something like
> SKIP: $TEST_NAME: Missing hardware features
> 
> once that is in place, we could revert this patch

But that would mean that on machines which don't support dumping, PV tests will never run, will they?

So we need some way of specifing at compile time whether you want dump support or not.