Re: [RFC v1 10/25] hw/core/loader: Add a ROM loader notifier

On Tue, Jul 14, 2026 at 08:52:43PM +1000, Gavin Shan wrote:
> On 7/8/26 8:42 AM, Mathieu Poirier wrote:
> > From: Jean-Philippe Brucker <[email protected]>
> > 
> > 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 <[email protected]>
> > Signed-off-by: Mathieu Poirier <[email protected]>
> > ---
> >   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..b3d769bec5cb 100644
> > --- a/hw/core/loader.c
> > +++ b/hw/core/loader.c
> > @@ -74,6 +74,8 @@
> >   #endif
> 
> The (edk2) firmware for the realm guest can be specified by the legacy
> '-drive if=pflash' or '-bios'. The memory region corresponding to the
> firmware image specified by '-bios' is recorded by the newly added notifier
> and populated to TF-RMM properly.
> 
> I don't see how the memory region corresponding to (edk2) firmware image
> specified by '-drive if=pflash' is recorded and populated to TF-RMM
> accordingly in this series. So I guess '-drive if=pflash' isn't supported
> yet?

Please give '-drive if=pflash' a try and let me know how you fare.  Edk2 is not
part of the bootstack I'm currently testing with but I know of configurations
where it does work.

I'll add it to my list of things to do if it doesn't work, though I may not
address it in this patchset.  We'll see how busy things get.

> 
> Note that I didn't give '-drive if=pflash' a try yet.
> 
> >   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,
> > +            .as = rom->as,
> > +        };
> > +        notifier_list_notify(&rom_loader_notifier, &notify);
> >       }
> >   }
> > diff --git a/include/hw/core/loader.h b/include/hw/core/loader.h
> > index d9431e8a8d12..94cf6ad2e26b 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;
> > +    /* Address space of the blob */
> > +    AddressSpace *as;
> > +} RomLoaderNotifyData;
> > +
> > +/**
> > + * 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
>