I have used your method to clean FSEG from unwanted date strings and added
a new fw_cfg to control the date that will eventually appear in SystemBiosDate.

New patches submitted.


On 24 May 2019, at 19:35, Sam Eiderman <> wrote:


Notice that your patch changes SystemBiosDate for legacy smbios users from 04/01/14 to 01/01/11 - I’m okay with this change.

Also notice that the RELEASE_DATE_STR[] in smbios.c has to be volatile or else it is optimized,
unlike BIOS_DATE[] which is used in a function call and is not optimized.

So the patch should be:

diff --git a/src/fw/biostables.c b/src/fw/biostables.c
index fe8626ef..718926d7 100644
--- a/src/fw/biostables.c
+++ b/src/fw/biostables.c
@@ -401,7 +401,7 @@ smbios_new_type_0(void *start,

#define BIOS_NAME "SeaBIOS"
-#define BIOS_DATE "04/01/2014"
+static const char BIOS_DATE[] = "04/01/2014";

static int

diff --git a/src/fw/smbios.c b/src/fw/smbios.c
index f3b5ad9d..fc4dcfe2 100644
--- a/src/fw/smbios.c
+++ b/src/fw/smbios.c

@@ -134,7 +141,7 @@ get_external(int type, char **p, unsigned *nr_structs,
            end += size;                                                \
            p->field = ++str_index;                                     \
        } else {                                                        \
-            memcpy(end, def, sizeof(def));                              \
+            memcpy(end, (void*)def, sizeof(def));                       \
            end += sizeof(def);                                         \
            p->field = ++str_index;                                     \
        }                                                               \
@@ -161,7 +168,7 @@ get_external(int type, char **p, unsigned *nr_structs,
    } while (0)

/* Type 0 -- BIOS Information */
-#define RELEASE_DATE_STR "01/01/2011"
+const char volatile RELEASE_DATE_STR[] = "01/01/2011";
static void *
smbios_init_type_0(void *start)


On 24 May 2019, at 7:52, Gerd Hoffmann <> wrote:


* Letting the user choose the date which will appear in the SystemBiosDate registry key
Under QEMU.

Ah, *this* is why qemu provides a type0 table.
What is the use case for this?

The thing is that SystemBiosDate is different than the value in, at least on a legacy bios.

Legacy SMBIOS Bios Date is '01/01/2011’

Maybe it's time add a config option to compile out support for legacy
acpi / smbios tables.  The qemu versions which need that are a few years
old meanwhile …

I don’t know who uses legacy smbios at the moment except for qemu machines < 2.1 but adding a config option is always nice.

Actually I think we used legacy smbios in v2v scenarios from VMware/PhoenixBios to QEMU/SeaBIOS (with hwversion < 12).


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