Re: [Qemu-devel] [PATCH] s390x: always provide pci support

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 11 Feb 2019 15:05:46 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 11.02.2019 12:32, Cornelia Huck wrote:
> > We tried to make pci support optional on s390x in the past;
> > unfortunately, we still require the s390 phb to be created
> > unconditionally due to backwards compatibility issues.
> > 
> > Instead of sinking more effort into this (including compat
> > handling for older machines etc.) for non-obvious gains, let's
> > just make CONFIG_PCI something that is always set on s390x.
> > 
> > Note that you can still fence off pci for the _guest_ if you
> > provide a cpu model without the zpci feature.
> > 
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>  
> 
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> 
> The previous attempts of making it configurable caused more  pain than
> benefit.

I think we've reaped all the benefits of the attempt already (making
relevant instructions check for the zpci feature bit).