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authorDov Murik <dovmurik@linux.ibm.com>2022-02-22 07:19:06 +0000
committerMichael S. Tsirkin <mst@redhat.com>2022-03-06 05:08:23 -0500
commit9919423516ddf0519df965184e236ba74fa236b1 (patch)
tree74f9054c343629206cdf01faad8820ca1a3a2258
parente5aaeac3554599ad5ca3c8ace38ad5bcd7ae6ff1 (diff)
hw/i386: Replace magic number with field length calculation
Replce the literal magic number 48 with length calculation (32 bytes at the end of the firmware after the table footer + 16 bytes of the OVMF table footer GUID). No functional change intended. Signed-off-by: Dov Murik <dovmurik@linux.ibm.com> Message-Id: <20220222071906.2632426-3-dovmurik@linux.ibm.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
-rw-r--r--hw/i386/pc_sysfw_ovmf.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/hw/i386/pc_sysfw_ovmf.c b/hw/i386/pc_sysfw_ovmf.c
index df15c9737b..07a4c267fa 100644
--- a/hw/i386/pc_sysfw_ovmf.c
+++ b/hw/i386/pc_sysfw_ovmf.c
@@ -30,6 +30,8 @@
#define OVMF_TABLE_FOOTER_GUID "96b582de-1fb2-45f7-baea-a366c55a082d"
+static const int bytes_after_table_footer = 32;
+
static bool ovmf_flash_parsed;
static uint8_t *ovmf_table;
static int ovmf_table_len;
@@ -53,12 +55,13 @@ void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size)
/*
* if this is OVMF there will be a table footer
- * guid 48 bytes before the end of the flash file. If it's
- * not found, silently abort the flash parsing.
+ * guid 48 bytes before the end of the flash file
+ * (= 32 bytes after the table + 16 bytes the GUID itself).
+ * If it's not found, silently abort the flash parsing.
*/
qemu_uuid_parse(OVMF_TABLE_FOOTER_GUID, &guid);
guid = qemu_uuid_bswap(guid); /* guids are LE */
- ptr = flash_ptr + flash_size - 48;
+ ptr = flash_ptr + flash_size - (bytes_after_table_footer + sizeof(guid));
if (!qemu_uuid_is_equal((QemuUUID *)ptr, &guid)) {
return;
}