Re: [PATCH] hw/qdev-core: Add compatibility for (non)-transitional devs

[Jean-Louis Dupond]

On 19/10/2021 17:27, Eduardo Habkost wrote:
> On Tue, Oct 12, 2021 at 10:24:28AM +0200, Jean-Louis Dupond wrote:
> > hw_compat modes only take into account their base name.
> What do you mean by "base name"?
virtio-net-pci (without the (non-)transitional extension.
> > But if a device is created with (non)-transitional, then the compat
> > values are not used, causing migrating issues.
> >
> > This commit adds their (non)-transitional entries with the same settings
> > as the base entry.
>
> Wouldn't it be easier to fix the incorrect compat_props arrays to
> use "virtio-*-pci-base" instead?
>
> If a piece of code is supposed to affect/support both
> non-transitional and transitional subclasses, that's why
> VirtioPCIDeviceTypeInfo.base_name exists.
Thats easier indeed :)
> > Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1999141
> >
> > Signed-off-by: Jean-Louis Dupond <jean-louis@dupond.be>
> > ---
> >   include/hw/qdev-core.h | 34 ++++++++++++++++++++++++++++++++++
> >   1 file changed, 34 insertions(+)
> >
> > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> > index 4ff19c714b..5726825c2d 100644
> > --- a/include/hw/qdev-core.h
> > +++ b/include/hw/qdev-core.h
> > @@ -293,6 +293,30 @@ typedef struct GlobalProperty {
> >       bool optional;
> >   } GlobalProperty;
> >   
> > +
> > +/**
> > + * Helper to add (non)transitional compat properties
> > + */
> > +static inline void
> > +compat_props_add_transitional(GPtrArray *arr, GlobalProperty *prop)
> > +{
> > +    GlobalProperty *transitional = g_new0(typeof(*transitional), 1);
> > +    transitional->driver = g_strdup_printf("%s-transitional", prop->driver);
> > +    transitional->property = g_strdup(prop->property);
> > +    transitional->value = g_strdup(prop->value);
> > +    transitional->used = prop->used;
> > +    transitional->optional = prop->optional;
> > +    g_ptr_array_add(arr, (void *)transitional);
> > +
> > +    GlobalProperty *non_transitional = g_new0(typeof(*non_transitional), 1);
> > +    non_transitional->driver = g_strdup_printf("%s-non-transitional", 
> > prop->driver);
> > +    non_transitional->property = g_strdup(prop->property);
> > +    non_transitional->value = g_strdup(prop->value);
> > +    non_transitional->used = prop->used;
> > +    non_transitional->optional = prop->optional;
> > +    g_ptr_array_add(arr, (void *)non_transitional);
> > +}
> > +
> >   static inline void
> >   compat_props_add(GPtrArray *arr,
> >                    GlobalProperty props[], size_t nelem)
> > @@ -300,6 +324,16 @@ compat_props_add(GPtrArray *arr,
> >       int i;
> >       for (i = 0; i < nelem; i++) {
> >           g_ptr_array_add(arr, (void *)&props[i]);
> > +        if (g_str_equal(props[i].driver, "vhost-user-blk-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-scsi-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-blk-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-balloon-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-serial-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-9p-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-net-pci") ||
> > +            g_str_equal(props[i].driver, "virtio-rng-pci")) {
> > +            compat_props_add_transitional(arr, &props[i]);
> > +        }
> >       }
> >   }
> >   
> > --
> > 2.33.0