Re: [PATCH v3 11/20] nubus-device: add romfile property for loading declaration ROMs

[Mark Cave-Ayland]

On 16/09/2021 14:06, Markus Armbruster wrote:

> Philippe Mathieu-Daudé <f4bug@amsat.org> writes:
>
> > On 9/16/21 12:05 PM, Mark Cave-Ayland wrote:
> > > The declaration ROM is located at the top-most address of the standard slot
> > > space.
> > >
> > > Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> > > ---
> > >   hw/nubus/nubus-device.c  | 43 +++++++++++++++++++++++++++++++++++++++-
> > >   include/hw/nubus/nubus.h |  6 ++++++
> > >   2 files changed, 48 insertions(+), 1 deletion(-)
> >
> > > @@ -38,10 +43,46 @@ static void nubus_device_realize(DeviceState *dev, Error 
> > > **errp)
> > >       memory_region_add_subregion(&nubus->slot_io, slot_offset,
> > >                                   &nd->slot_mem);
> > >       g_free(name);
> > > +
> > > +    /* Declaration ROM */
> > > +    if (nd->romfile != NULL) {
> > > +        path = qemu_find_file(QEMU_FILE_TYPE_BIOS, nd->romfile);
> > > +        if (path == NULL) {
> > > +            path = g_strdup(nd->romfile);
> > > +        }
> > > +
> > > +        size = get_image_size(path);
> > > +        if (size < 0) {
> > > +            error_setg(errp, "failed to find romfile \"%s\"", nd->romfile);
> > > +            g_free(path);
> > > +            return;
> > > +        } else if (size == 0) {
> > > +            error_setg(errp, "romfile \"%s\" is empty", nd->romfile);
> > > +            g_free(path);
> > > +            return;
> > > +        } else if (size > NUBUS_DECL_ROM_MAX_SIZE) {
> > > +            error_setg(errp, "romfile \"%s\" too large (maximum size 128K)",
> > > +                       nd->romfile);
> > > +            g_free(path);
> > > +            return;
> > > +        }
> > > +
> > > +        name = g_strdup_printf("nubus-slot-%x-declaration-rom", nd->slot);
> > > +        memory_region_init_rom(&nd->decl_rom, OBJECT(dev), name, size,
> > > +                               &error_fatal);
>
> Is this error expected to happen?
>
> If yes, you should quite probably propagate it.
>
> If no, &error_abort.

(goes and looks)

Ultimately this gets set from memory_region_init_rom_device_nomigrate() where err is 
returned from qemu_ram_alloc() which is fairly fatal. So I guess this should be 
&error_abort then?

Note that I copied that part of the logic from hw/pci/pci.c's pci_add_option_rom() so 
it may also need to be adjusted there.

> > > +        ret = load_image_mr(path, &nd->decl_rom);
> >
> > load_image_mr() already calls get_image_size(), rom_add_file() and
> > qemu_find_file(). *But* it doesn't takes and Error handle, and report
> > error using fprintf()...
>
> ... except when they don't:
>
>      int load_image_mr(const char *filename, MemoryRegion *mr)
>      {
>          int size;
>
>          if (!memory_access_is_direct(mr, false)) {
>              /* Can only load an image into RAM or ROM */
> --->        return -1;
>          }
>
>          size = get_image_size(filename);
>
>          if (size < 0 || size > memory_region_size(mr)) {
>              return -1;
>          }
>          if (size > 0) {
>              if (rom_add_file_mr(filename, mr, -1) < 0) {
>                  return -1;
>              }
>          }
>          return size;
>      }
>
> Hot mess!
>
> >                           So unfortunately rom_add*() functions are
> > kinda outdated and you are doing the right thing to propagate detailled
> > errors.
>
> I can't see errors being propagated, only a warn_report()...
>
> >          Therefore:
> >
> > Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> >
> > > +        g_free(path);
> > > +        if (ret < 0) {
> > > +            warn_report("nubus-device: could not load prom '%s'", nd->romfile);
>
> ... here.

Looking again at pci_add_option_rom() then perhaps this should be error_setg() 
instead: if you are explicitly trying to load a ROM image, then you should at least 
be able to get the filename correct.

> > > +        }
> > > +        memory_region_add_subregion(&nd->slot_mem, NUBUS_SLOT_SIZE - size,
> > > +                                    &nd->decl_rom);
> > > +    }
> > >   }


ATB,

Mark.