[PATCH v4 0/4] Add support for zboot images compressed with zstd

[PATCH v4 0/4] Add support for zboot images compressed with zstd

[Daan De Meyer]

Fedora arm64 has an EFI_ZBOOT kernel image compressed
with zstd. Let's make sure we can use it for direct kernel
boot with qemu.

Daan De Meyer (4):
  Rename LOAD_IMAGE_MAX_GUNZIP_BYTES to
    LOAD_IMAGE_MAX_DECOMPRESSED_BYTES
  Rename UBOOT_MAX_GUNZIP_BYTES to UBOOT_MAX_DECOMPRESSED_BYTES
  Use g_autofree in unpack_efi_zboot_image()
  Add support for zboot images compressed with zstd

 hw/arm/boot.c        |  4 ++--
 hw/core/loader-fit.c |  2 +-
 hw/core/loader.c     | 44 ++++++++++++++++++++++++++++----------------
 hw/nvram/fw_cfg.c    |  2 +-
 include/hw/loader.h  |  4 ++--
 5 files changed, 34 insertions(+), 22 deletions(-)

-- 
2.51.1

[PATCH v4 1/4] Rename LOAD_IMAGE_MAX_GUNZIP_BYTES to LOAD_IMAGE_MAX_DECOMPRESSED_BYTES

[Daan De Meyer]

Preparation for adding support for zstd compressed efi zboot kernel
images.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
---
 hw/arm/boot.c       | 4 ++--
 hw/core/loader.c    | 9 +++++----
 hw/nvram/fw_cfg.c   | 2 +-
 include/hw/loader.h | 2 +-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index b91660208f..6cf8a4b7fd 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -823,11 +823,11 @@ 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;
+    size_t max_size = LOAD_IMAGE_MAX_DECOMPRESSED_BYTES;
     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,
-                                     &buffer);
+    size = load_image_gzipped_buffer(filename, max_size, &buffer);
 
     if (size < 0) {
         gsize len;
diff --git a/hw/core/loader.c b/hw/core/loader.c
index 590c5b02aa..f940b6a227 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -814,8 +814,8 @@ ssize_t load_image_gzipped_buffer(const char *filename, uint64_t max_sz,
         goto out;
     }
 
-    if (max_sz > LOAD_IMAGE_MAX_GUNZIP_BYTES) {
-        max_sz = LOAD_IMAGE_MAX_GUNZIP_BYTES;
+    if (max_sz > LOAD_IMAGE_MAX_DECOMPRESSED_BYTES) {
+        max_sz = LOAD_IMAGE_MAX_DECOMPRESSED_BYTES;
     }
 
     data = g_malloc(max_sz);
@@ -885,6 +885,7 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
     uint8_t *data = NULL;
     ssize_t ploff, plsize;
     ssize_t bytes;
+    size_t max_bytes = LOAD_IMAGE_MAX_DECOMPRESSED_BYTES;
 
     /* ignore if this is too small to be a EFI zboot image */
     if (*size < sizeof(*header)) {
@@ -916,8 +917,8 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
         return -1;
     }
 
-    data = g_malloc(LOAD_IMAGE_MAX_GUNZIP_BYTES);
-    bytes = gunzip(data, LOAD_IMAGE_MAX_GUNZIP_BYTES, *buffer + ploff, plsize);
+    data = g_malloc(max_bytes);
+    bytes = gunzip(data, max_bytes, *buffer + ploff, plsize);
     if (bytes < 0) {
         fprintf(stderr, "failed to decompress EFI zboot image\n");
         g_free(data);
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index aa24050493..af3b112524 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -1115,7 +1115,7 @@ void load_image_to_fw_cfg(FWCfgState *fw_cfg, uint16_t size_key,
 
     if (try_decompress) {
         size = load_image_gzipped_buffer(image_name,
-                                         LOAD_IMAGE_MAX_GUNZIP_BYTES, &data);
+                                         LOAD_IMAGE_MAX_DECOMPRESSED_BYTES, &data);
     }
 
     if (size == (size_t)-1) {
diff --git a/include/hw/loader.h b/include/hw/loader.h
index d035e72748..3371de506f 100644
--- a/include/hw/loader.h
+++ b/include/hw/loader.h
@@ -82,7 +82,7 @@ ssize_t load_image_mr(const char *filename, MemoryRegion *mr);
  * load_image_gzipped_buffer() will read. It prevents
  * g_malloc() in those functions from allocating a huge amount of memory.
  */
-#define LOAD_IMAGE_MAX_GUNZIP_BYTES (256 << 20)
+#define LOAD_IMAGE_MAX_DECOMPRESSED_BYTES (256 << 20)
 
 ssize_t load_image_gzipped_buffer(const char *filename, uint64_t max_sz,
                                   uint8_t **buffer);
-- 
2.51.1

[PATCH v4 2/4] Rename UBOOT_MAX_GUNZIP_BYTES to UBOOT_MAX_DECOMPRESSED_BYTES

[Daan De Meyer]

For consistency with LOAD_IMAGE_MAX_DECOMPRESSED_BYTES.

Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
---
 hw/core/loader-fit.c | 2 +-
 hw/core/loader.c     | 2 +-
 include/hw/loader.h  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/core/loader-fit.c b/hw/core/loader-fit.c
index 2dea485ae0..5895e89f22 100644
--- a/hw/core/loader-fit.c
+++ b/hw/core/loader-fit.c
@@ -70,7 +70,7 @@ static void *fit_load_image_alloc(const void *itb, const char *name,
     }
 
     if (!strcmp(comp, "gzip")) {
-        uncomp_len = UBOOT_MAX_GUNZIP_BYTES;
+        uncomp_len = UBOOT_MAX_DECOMPRESSED_BYTES;
         uncomp_data = g_malloc(uncomp_len);
 
         uncomp_len = gunzip(uncomp_data, uncomp_len, (void *) data, sz);
diff --git a/hw/core/loader.c b/hw/core/loader.c
index f940b6a227..090af59df2 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -739,7 +739,7 @@ static ssize_t load_uboot_image(const char *filename, hwaddr *ep,
         ssize_t bytes;
 
         compressed_data = data;
-        max_bytes = UBOOT_MAX_GUNZIP_BYTES;
+        max_bytes = UBOOT_MAX_DECOMPRESSED_BYTES;
         data = g_malloc(max_bytes);
 
         bytes = gunzip(data, max_bytes, compressed_data, hdr->ih_size);
diff --git a/include/hw/loader.h b/include/hw/loader.h
index 3371de506f..cbcb274fce 100644
--- a/include/hw/loader.h
+++ b/include/hw/loader.h
@@ -343,7 +343,7 @@ ssize_t rom_add_option(const char *file, int32_t bootindex);
 
 /* This is the usual maximum in uboot, so if a uImage overflows this, it would
  * overflow on real hardware too. */
-#define UBOOT_MAX_GUNZIP_BYTES (64 << 20)
+#define UBOOT_MAX_DECOMPRESSED_BYTES (64 << 20)
 
 typedef struct RomGap {
     hwaddr base;
-- 
2.51.1

[PATCH v4 3/4] Use g_autofree in unpack_efi_zboot_image()

[Daan De Meyer]

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
---
 hw/core/loader.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index 090af59df2..d74e33ceb6 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -882,7 +882,7 @@ struct linux_efi_zboot_header {
 ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
 {
     const struct linux_efi_zboot_header *header;
-    uint8_t *data = NULL;
+    g_autofree uint8_t *data = NULL;
     ssize_t ploff, plsize;
     ssize_t bytes;
     size_t max_bytes = LOAD_IMAGE_MAX_DECOMPRESSED_BYTES;
@@ -921,12 +921,11 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
     bytes = gunzip(data, max_bytes, *buffer + ploff, plsize);
     if (bytes < 0) {
         fprintf(stderr, "failed to decompress EFI zboot image\n");
-        g_free(data);
         return -1;
     }
 
     g_free(*buffer);
-    *buffer = g_realloc(data, bytes);
+    *buffer = g_realloc(g_steal_pointer(&data), bytes);
     *size = bytes;
     return bytes;
 }
-- 
2.51.1

[PATCH v4 4/4] Add support for zboot images compressed with zstd

[Daan De Meyer]

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
---
 hw/core/loader.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index d74e33ceb6..8924767e7d 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -68,6 +68,11 @@
 
 #include <zlib.h>
 
+#ifdef CONFIG_ZSTD
+#include <zstd.h>
+#include <zstd_errors.h>
+#endif
+
 static int roms_loaded;
 
 /* return the size or -1 if error */
@@ -901,14 +906,6 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
         return 0;
     }
 
-    if (strcmp(header->compression_type, "gzip") != 0) {
-        fprintf(stderr,
-                "unable to handle EFI zboot image with \"%.*s\" compression\n",
-                (int)sizeof(header->compression_type) - 1,
-                header->compression_type);
-        return -1;
-    }
-
     ploff = ldl_le_p(&header->payload_offset);
     plsize = ldl_le_p(&header->payload_size);
 
@@ -918,7 +915,22 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
     }
 
     data = g_malloc(max_bytes);
-    bytes = gunzip(data, max_bytes, *buffer + ploff, plsize);
+
+    if (strcmp(header->compression_type, "gzip") == 0) {
+        bytes = gunzip(data, max_bytes, *buffer + ploff, plsize);
+#ifdef CONFIG_ZSTD
+    } else if (strcmp(header->compression_type, "zstd") == 0) {
+        size_t ret = ZSTD_decompress(data, max_bytes, *buffer + ploff, plsize);
+        bytes = ZSTD_isError(ret) ? -1 : (ssize_t) ret;
+#endif
+    } else {
+        fprintf(stderr,
+                "unable to handle EFI zboot image with \"%.*s\" compression\n",
+                (int)sizeof(header->compression_type) - 1,
+                header->compression_type);
+        return -1;
+    }
+
     if (bytes < 0) {
         fprintf(stderr, "failed to decompress EFI zboot image\n");
         return -1;
-- 
2.51.1

Re: [PATCH v4 2/4] Rename UBOOT_MAX_GUNZIP_BYTES to UBOOT_MAX_DECOMPRESSED_BYTES

[Philippe Mathieu-Daudé]

On 24/11/25 13:35, Daan De Meyer wrote:
> For consistency with LOAD_IMAGE_MAX_DECOMPRESSED_BYTES.
> 
> Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
> ---
>   hw/core/loader-fit.c | 2 +-
>   hw/core/loader.c     | 2 +-
>   include/hw/loader.h  | 2 +-
>   3 files changed, 3 insertions(+), 3 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Re: [PATCH v4 0/4] Add support for zboot images compressed with zstd

[Philippe Mathieu-Daudé]

On 24/11/25 13:35, Daan De Meyer wrote:
> Fedora arm64 has an EFI_ZBOOT kernel image compressed
> with zstd. Let's make sure we can use it for direct kernel
> boot with qemu.
> 
> Daan De Meyer (4):
>    Rename LOAD_IMAGE_MAX_GUNZIP_BYTES to
>      LOAD_IMAGE_MAX_DECOMPRESSED_BYTES
>    Rename UBOOT_MAX_GUNZIP_BYTES to UBOOT_MAX_DECOMPRESSED_BYTES
>    Use g_autofree in unpack_efi_zboot_image()
>    Add support for zboot images compressed with zstd

Thanks, queued for 11.0.