RE: [PATCH v4] hw/core/loader: allow loading larger ROMs

[Xingtao Yao (Fujitsu)]

Reviewed-by: Xingtao Yao <yaoxt.fnst@fujitsu.com>

> -----Original Message-----
> From: Gregor Haas <gregorhaas1997@gmail.com>
> Sent: Saturday, June 29, 2024 2:27 AM
> To: qemu-devel@nongnu.org
> Cc: berrange@redhat.com; Yao, Xingtao/姚 幸涛 <yaoxt.fnst@fujitsu.com>;
> Gregor Haas <gregorhaas1997@gmail.com>
> Subject: [PATCH v4] hw/core/loader: allow loading larger ROMs
> 
> The read() syscall is not guaranteed to return all data from a file. The
> default ROM loader implementation currently does not take this into account,
> instead failing if all bytes are not read at once. This change loads the ROM
> using g_file_get_contents() instead, which correctly reads all data using
> multiple calls to read() while also returning the loaded ROM size.
> 
> Signed-off-by: Gregor Haas <gregorhaas1997@gmail.com>
> ---
>  hw/core/loader.c | 30 +++++-------------------------
>  1 file changed, 5 insertions(+), 25 deletions(-)
> 
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index 2f8105d7de..44444a5714 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -1075,8 +1075,7 @@ ssize_t rom_add_file(const char *file, const char 
> *fw_dir,
>  {
>      MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
>      Rom *rom;
> -    ssize_t rc;
> -    int fd = -1;
> +    g_autoptr(GError) gerr = NULL;
>      char devpath[100];
> 
>      if (as && mr) {
> @@ -1094,35 +1093,19 @@ ssize_t rom_add_file(const char *file, const char
> *fw_dir,
>          rom->path = g_strdup(file);
>      }
> 
> -    fd = open(rom->path, O_RDONLY | O_BINARY);
> -    if (fd == -1) {
> -        fprintf(stderr, "Could not open option rom '%s': %s\n",
> -                rom->path, strerror(errno));
> -        goto err;
> -    }
> -
>      if (fw_dir) {
>          rom->fw_dir  = g_strdup(fw_dir);
>          rom->fw_file = g_strdup(file);
>      }
>      rom->addr     = addr;
> -    rom->romsize  = lseek(fd, 0, SEEK_END);
> -    if (rom->romsize == -1) {
> -        fprintf(stderr, "rom: file %-20s: get size error: %s\n",
> -                rom->name, strerror(errno));
> +    if (!g_file_get_contents(rom->path, (gchar **) &rom->data,
> +                             &rom->romsize, &gerr)) {
> +        fprintf(stderr, "rom: file %-20s: error %s\n",
> +                rom->name, gerr->message);
>          goto err;
>      }
> 
>      rom->datasize = rom->romsize;
> -    rom->data     = g_malloc0(rom->datasize);
> -    lseek(fd, 0, SEEK_SET);
> -    rc = read(fd, rom->data, rom->datasize);
> -    if (rc != rom->datasize) {
> -        fprintf(stderr, "rom: file %-20s: read error: rc=%zd (expected 
> %zd)\n",
> -                rom->name, rc, rom->datasize);
> -        goto err;
> -    }
> -    close(fd);
>      rom_insert(rom);
>      if (rom->fw_file && fw_cfg) {
>          const char *basename;
> @@ -1159,9 +1142,6 @@ ssize_t rom_add_file(const char *file, const char 
> *fw_dir,
>      return 0;
> 
>  err:
> -    if (fd != -1)
> -        close(fd);
> -
>      rom_free(rom);
>      return -1;
>  }
> --
> 2.45.2