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

[Gavin Shan <gshan@redhat.com>]

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;


> +/**
> + * 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