hw/core/loader: Use ssize_t for efi zboot unpacker

Convert to use sszie_t to represent size internally to avoid
large image overflowing the size.

Suggested-by: Richard Henderson <[email protected]>
Signed-off-by: Jiaxun Yang <[email protected]>
Signed-off-by: Bibo Mao <[email protected]>
Reviewed-by: Bibo Mao <[email protected]>

Author: FlyGoat

hw/arm/boot.c

@@ -857,7 +857,7 @@ static uint64_t load_aarch64_image(const char *filename, hwaddr mem_base,
     hwaddr kernel_load_offset = KERNEL64_LOAD_ADDR;
     uint64_t kernel_size = 0;
     uint8_t *buffer;
-    int size;
+    ssize_t size;
 
     /* On aarch64, it's the bootloader's job to uncompress the kernel. */
     size = load_image_gzipped_buffer(filename, LOAD_IMAGE_MAX_GUNZIP_BYTES,

hw/core/loader.c

@@ -886,11 +886,11 @@ struct linux_efi_zboot_header {
  *
  * If the image is not a Linux EFI zboot image, do nothing and return success.
  */
-ssize_t unpack_efi_zboot_image(uint8_t **buffer, int *size)
+ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
 {
     const struct linux_efi_zboot_header *header;
     uint8_t *data = NULL;
-    int ploff, plsize;
+    ssize_t ploff, plsize;
     ssize_t bytes;
 
     /* ignore if this is too small to be a EFI zboot image */

include/hw/loader.h

@@ -101,7 +101,7 @@ ssize_t load_image_gzipped_buffer(const char *filename, uint64_t max_sz,
  * Returns the size of the decompressed payload if decompression was performed
  * successfully.
  */
-ssize_t unpack_efi_zboot_image(uint8_t **buffer, int *size);
+ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size);
 
 #define ELF_LOAD_FAILED       -1
 #define ELF_LOAD_NOT_ELF      -2