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 a511888aa3..c1611cc960 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -67,6 +67,11 @@
 
 #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 */
@@ -882,14 +887,6 @@ 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);
 
@@ -899,7 +896,22 @@ ssize_t unpack_efi_zboot_image(uint8_t **buffer, ssize_t *size)
     }
 
     data = g_malloc(LOAD_IMAGE_MAX_DECOMPRESSED_BYTES);
-    bytes = gunzip(data, LOAD_IMAGE_MAX_DECOMPRESSED_BYTES, *buffer + ploff, plsize);
+
+    if (strcmp(header->compression_type, "gzip") == 0) {
+        bytes = gunzip(data, LOAD_IMAGE_MAX_DECOMPRESSED_BYTES, *buffer + ploff, plsize);
+#ifdef CONFIG_ZSTD
+    } else if (strcmp(header->compression_type, "zstd") == 0) {
+        size_t ret = ZSTD_decompress(data, LOAD_IMAGE_MAX_DECOMPRESSED_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;
-- 
2.51.0

On Sat, Oct 11, 2025 at 10:15:53AM +0200, Daan De Meyer wrote:
> Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
> ---
>  hw/core/loader.c | 30 +++++++++++++++++++++---------
>  1 file changed, 21 insertions(+), 9 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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