Linux, besides CPIO, supports 7 different compressed formats for the initrd
(gzip, bzip2, LZMA, XZ, LZO, LZ4, ZSTD), but kvmtool only recognizes one of
them.
Remove the initrd magic check because:
1. It doesn't bring much to the end user, as the Linux kernel still
complains if the initrd is in an unknown format.
2. --kernel can be used to load something that is not a Linux kernel (like
a kvm-unit-tests test), in which case a format which is not supported by
a Linux kernel can still be perfectly valid. For example, kvm-unit-tests
load the test environment as an initrd in plain ASCII format.
3. It cuts down on the maintenance effort when new formats are added to
the Linux kernel. Not a big deal, since that doesn't happen very often,
but it's still an effort with very little gain (see point #1 above).
Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
---
kvm.c | 22 ----------------------
1 file changed, 22 deletions(-)
diff --git a/kvm.c b/kvm.c
index 5bc66c8be82a..952ef1fbb41c 100644
--- a/kvm.c
+++ b/kvm.c
@@ -512,25 +512,6 @@ err:
}
core_init(kvm__init);
-/* RFC 1952 */
-#define GZIP_ID1 0x1f
-#define GZIP_ID2 0x8b
-#define CPIO_MAGIC "0707"
-/* initrd may be gzipped, or a plain cpio */
-static bool initrd_check(int fd)
-{
- unsigned char id[4];
-
- if (read_in_full(fd, id, ARRAY_SIZE(id)) < 0)
- return false;
-
- if (lseek(fd, 0, SEEK_SET) < 0)
- die_perror("lseek");
-
- return (id[0] == GZIP_ID1 && id[1] == GZIP_ID2) ||
- !memcmp(id, CPIO_MAGIC, 4);
-}
-
bool kvm__load_kernel(struct kvm *kvm, const char *kernel_filename,
const char *initrd_filename, const char *kernel_cmdline)
{
@@ -545,9 +526,6 @@ bool kvm__load_kernel(struct kvm *kvm, const char *kernel_filename,
fd_initrd = open(initrd_filename, O_RDONLY);
if (fd_initrd < 0)
die("Unable to open initrd %s", initrd_filename);
-
- if (!initrd_check(fd_initrd))
- die("%s is not an initrd", initrd_filename);
}
ret = kvm__arch_load_kernel_image(kvm, fd_kernel, fd_initrd,
--
2.31.1
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