Re: [RFC v4 09/24] hw/core/loader: Add a ROM loader notifier

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Fri, Oct 02, 2026 at 11:15:08AM +1000, Gavin Shan wrote:
> On 9/4/26 5:35 AM, Mathieu Poirier wrote:
> > From: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > 
> > Add a function to register a notifier that is invoked when ROMs get
> > loaded into guest memory.
> > 
> > It will be used by Arm confidential guest support, in order to register
> > all blobs loaded into memory with KVM, so that their content is moved
> > into Realm state and measured into the initial VM state.
> > 
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@linaro.org>
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > ---
> >   hw/core/loader.c         | 15 +++++++++++++++
> >   include/hw/core/loader.h | 17 +++++++++++++++++
> >   2 files changed, 32 insertions(+)
> > 
> > diff --git a/hw/core/loader.c b/hw/core/loader.c
> > index 5cbfba0a86d2..388f10e828db 100644
> > --- a/hw/core/loader.c
> > +++ b/hw/core/loader.c
> > @@ -74,6 +74,8 @@
> >   #endif
> >   static int roms_loaded;
> > +static NotifierList rom_loader_notifier =
> > +    NOTIFIER_LIST_INITIALIZER(rom_loader_notifier);
> >   /* return the size or -1 if error */
> >   int64_t get_image_size(const char *filename, Error **errp)
> > @@ -1201,6 +1203,11 @@ MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
> >       return mr;
> >   }
> > +void rom_add_load_notifier(Notifier *notifier)
> > +{
> > +    notifier_list_add(&rom_loader_notifier, notifier);
> > +}
> > +
> >   /* This function is specific for elf program because we don't need to allocate
> >    * all the rom. We just allocate the first part and the rest is just zeros. This
> >    * is why romsize and datasize are different. Also, this function takes its own
> > @@ -1242,6 +1249,7 @@ ssize_t rom_add_option(const char *file, int32_t bootindex)
> >   static void rom_reset(void *unused)
> >   {
> >       Rom *rom;
> > +    RomLoaderNotifyData notify;
> >       QTAILQ_FOREACH(rom, &roms, next) {
> >           if (rom->fw_file) {
> > @@ -1290,6 +1298,13 @@ static void rom_reset(void *unused)
> >           address_space_flush_icache_range(rom->as, rom->addr, rom->datasize);
> >           trace_loader_write_rom(rom->name, rom->addr, rom->datasize, rom->isrom);
> > +
> > +        notify = (RomLoaderNotifyData) {
> > +            .addr = rom->addr,
> > +            .len = rom->datasize,
> > +            .data = rom->data,
> > +        };
> > +        notifier_list_notify(&rom_loader_notifier, &notify);
> >       }
> >   }
> > diff --git a/include/hw/core/loader.h b/include/hw/core/loader.h
> > index d9431e8a8d12..fdfddfa7443e 100644
> > --- a/include/hw/core/loader.h
> > +++ b/include/hw/core/loader.h
> > @@ -342,6 +342,23 @@ void *rom_ptr_for_as(AddressSpace *as, hwaddr addr, size_t size);
> >   ssize_t rom_add_vga(const char *file);
> >   ssize_t rom_add_option(const char *file, int32_t bootindex);
> > +typedef struct RomLoaderNotifyData {
> > +    /* Address of the blob in guest memory */
> > +    hwaddr addr;
> > +    /* Length of the blob */
> > +    size_t len;
> > +    /* Blog data */
>           ^^^^
> I guess it would be 'Blob'.
> 
> > +    uint8_t *data;
> > +} RomLoaderNotifyData;
> > +
> 
> There are enough space at the tail of field declaration lines, where the
> comments can be put:
> 
> typedef struct RomLoaderNotifyData {
>     hwaddr  addr;   /* Address of the blob in guest memory */
>     size_t  len;    /* Length of the blob */
>     uint8_t *data;  /* Blob data */
> } RomLoaderNotifyData;
>

Fixed
 
> 
> > +/**
> > + * rom_add_load_notifier - Add a notifier for loaded images
> > + *
> > + * Add a notifier that will be invoked with a RomLoaderNotifyData structure for
> > + * each blob loaded into guest memory, after the blob is loaded.
> > + */
> > +void rom_add_load_notifier(Notifier *notifier);
> > +
> >   /* This is the usual maximum in uboot, so if a uImage overflows this, it would
> >    * overflow on real hardware too. */
> >   #define UBOOT_MAX_DECOMPRESSED_BYTES (64 << 20)
> 
> Thanks,
> Gavin
>