[Qemu-devel] [PATCH] SMBIOS: Update Type 0 struct generator for machines >= 2.1

[Gabriel L. Somlo]

A type 0 (bios info) smbios structure is only generated if explicitly
requested on the command line. This patch updates the mechanism for
generating this type of structure as follows:

  - convert bios_characteristics field to uin64_t (instead of uint8_t[8])
    as described in the current smbios spec (v2.8)

  - enable "virtual machine" bit in bios_characteristics_extension_bits

  - add command line option to enable "uefi supported" bit in
    bios_characteristics_extension_bits

These updates should make this optional smbios structure more useful when
used with edk2/ovmf. Only pc machines 2.1 and newer are affected, and only
when the user explicitly requests that a type 0 struct be generated.

Signed-off-by: Gabriel Somlo <address@hidden>
---

On Mon, May 12, 2014 at 11:20:15PM +0200, Laszlo Ersek wrote:
> I think exposing the bios extension bytes on the qemu
> command line (for saying "virtual machine" and "UEFI supported") is more
> important [...]

I think the "virtual machine" bit shouldn't be negotiable. I added an
option to flip the "uefi" bit from the command line. Also cleaned up
the bios_characteristics field in the process.

Let me know what you all think.

Thanks,
  Gabriel

 hw/i386/smbios.c         | 18 +++++++++++-------
 include/hw/i386/smbios.h |  2 +-
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/hw/i386/smbios.c b/hw/i386/smbios.c
index 7660718..b91d45e 100644
--- a/hw/i386/smbios.c
+++ b/hw/i386/smbios.c
@@ -67,7 +67,7 @@ static DECLARE_BITMAP(have_fields_bitmap, SMBIOS_MAX_TYPE+1);
 
 static struct {
     const char *vendor, *version, *date;
-    bool have_major_minor;
+    bool have_major_minor, uefi;
     uint8_t major, minor;
 } type0;
 
@@ -134,6 +134,10 @@ static const QemuOptDesc qemu_smbios_type0_opts[] = {
         .name = "release",
         .type = QEMU_OPT_STRING,
         .help = "revision number",
+    },{
+        .name = "uefi",
+        .type = QEMU_OPT_BOOL,
+        .help = "uefi support",
     },
     { /* end of list */ }
 };
@@ -497,13 +501,12 @@ static void smbios_build_type_0_table(void)
 
     t->bios_rom_size = 0; /* hardcoded in SeaBIOS with FIXME comment */
 
-    /* BIOS characteristics not supported */
-    memset(t->bios_characteristics, 0, 8);
-    t->bios_characteristics[0] = 0x08;
-
-    /* Enable targeted content distribution (needed for SVVP, per SeaBIOS) */
+    t->bios_characteristics = 0x08; /* Not supported */
     t->bios_characteristics_extension_bytes[0] = 0;
-    t->bios_characteristics_extension_bytes[1] = 4;
+    t->bios_characteristics_extension_bytes[1] = 0x14; /* TCD/SVVP | VM */
+    if (type0.uefi) {
+        t->bios_characteristics_extension_bytes[1] |= 0x08; /* |= UEFI */
+    }
 
     if (type0.have_major_minor) {
         t->system_bios_major_release = type0.major;
@@ -977,6 +980,7 @@ void smbios_entry_add(QemuOpts *opts)
             save_opt(&type0.vendor, opts, "vendor");
             save_opt(&type0.version, opts, "version");
             save_opt(&type0.date, opts, "date");
+            type0.uefi = qemu_opt_get_bool(opts, "uefi", false);
 
             val = qemu_opt_get(opts, "release");
             if (val) {
diff --git a/include/hw/i386/smbios.h b/include/hw/i386/smbios.h
index 6d854b7..5583f60 100644
--- a/include/hw/i386/smbios.h
+++ b/include/hw/i386/smbios.h
@@ -64,7 +64,7 @@ struct smbios_type_0 {
     uint16_t bios_starting_address_segment;
     uint8_t bios_release_date_str;
     uint8_t bios_rom_size;
-    uint8_t bios_characteristics[8];
+    uint64_t bios_characteristics;
     uint8_t bios_characteristics_extension_bytes[2];
     uint8_t system_bios_major_release;
     uint8_t system_bios_minor_release;
-- 
1.9.0