Re: [PATCH v10 11/12] hw/pci: Convert rom_bar into OnOffAuto

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jul 03, 2024 at 04:15:23AM +0200, BALATON Zoltan wrote:
> On Tue, 2 Jul 2024, Michael S. Tsirkin wrote:
> > On Thu, Jun 27, 2024 at 03:08:00PM +0900, Akihiko Odaki wrote:
> > > rom_bar is tristate but was defined as uint32_t so convert it into
> > > OnOffAuto.
> > > 
> > > Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> > 
> > Commit log should explain why this is an improvement,
> > not just what's done.
> > 
> > 
> > > diff --git a/docs/igd-assign.txt b/docs/igd-assign.txt
> > > index e17bb50789ad..35c6c8e28493 100644
> > > --- a/docs/igd-assign.txt
> > > +++ b/docs/igd-assign.txt
> > > @@ -35,7 +35,7 @@ IGD has two different modes for assignment using vfio-pci:
> > >        ISA/LPC bridge device (vfio-pci-igd-lpc-bridge) on the root bus at
> > >        PCI address 1f.0.
> > >      * The IGD device must have a VGA ROM, either provided via the romfile
> > > -      option or loaded automatically through vfio (standard).  rombar=0
> > > +      option or loaded automatically through vfio (standard).  rombar=off
> > >        will disable legacy mode support.
> > >      * Hotplug of the IGD device is not supported.
> > >      * The IGD device must be a SandyBridge or newer model device.
> > 
> > ...
> > 
> > > diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> > > index 39dae72497e0..0e920ed0691a 100644
> > > --- a/hw/vfio/pci-quirks.c
> > > +++ b/hw/vfio/pci-quirks.c
> > > @@ -33,7 +33,7 @@
> > >   * execution as noticed with the BCM 57810 card for lack of a
> > >   * more better way to handle such issues.
> > >   * The  user can still override by specifying a romfile or
> > > - * rombar=1.
> > > + * rombar=on.
> > >   * Please see https://bugs.launchpad.net/qemu/+bug/1284874
> > >   * for an analysis of the 57810 card hang. When adding
> > >   * a new vendor id/device id combination below, please also add
> > 
> > 
> > So we are apparently breaking a bunch of users who followed
> > documentation to the dot. Why is this a good idea?
> 
> On/off is clearer than 1/0. But isn't 1/0 a synonym for on/off so previous
> command lines would still work?
> 
> Regards,
> BALATON Zoltan

I see nothing in code that would make it so:


const QEnumLookup OnOffAuto_lookup = {
    .array = (const char *const[]) {
        [ON_OFF_AUTO_AUTO] = "auto",
        [ON_OFF_AUTO_ON] = "on",
        [ON_OFF_AUTO_OFF] = "off",
    },
    .size = ON_OFF_AUTO__MAX
};

I also tried with an existing property:

$ ./qemu-system-x86_64 -device intel-hda,msi=0
qemu-system-x86_64: -device intel-hda,msi=0: Parameter 'msi' does not accept value '0'


-- 
MST