[PATCH] smbios: entry-point-type option

[Eduardo Habkost]

Add command-line option that lets the SMBIOS entry point type to
be configured.

SMBIOS 3.0 support is necessary to allow us to support more
than 720 VCPUs in x86_64, due to SMBIOS 2.1 table size limits.

Note that it's still up to firmware to decide whether to generate
SMBIOS 2.1 and/or 3.0 entry points for the guest, using the
information contained in etc/smbios/smbios-anchor.  OVMF, for
example, is able to generate both entry points, depending on the
value of PcdSmbiosEntryPointProvideMethod.

The SMBIOS 3.0 entry point won't be enabled by default because it
is not supported yet by Seabios.  This may be changed once
Seabios starts supporting SMBIOS 3.0 entry points.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Laszlo, Philippe: do you know how exactly the value of
PcdSmbiosEntryPointProvideMethod is chosen when running OVMF?
---
 hw/smbios/smbios.c | 39 +++++++++++++++++++++++++++++++++++++--
 qemu-options.hx    | 16 +++++++++++++++-
 2 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
index 6a3d39793b..ed5cf7fa9a 100644
--- a/hw/smbios/smbios.c
+++ b/hw/smbios/smbios.c
@@ -62,6 +62,7 @@ size_t smbios_tables_len;
 unsigned smbios_table_max;
 unsigned smbios_table_cnt;
 static SmbiosEntryPointType smbios_ep_type = SMBIOS_ENTRY_POINT_21;
+static bool smbios_ep_type_set;
 
 static SmbiosEntryPoint ep;
 
@@ -139,6 +140,15 @@ static const QemuOptDesc qemu_smbios_file_opts[] = {
     { /* end of list */ }
 };
 
+static const QemuOptDesc qemu_smbios_entry_point_opts[] = {
+    {
+        .name = "entry-point-type",
+        .type = QEMU_OPT_STRING,
+        .help = "SMBIOS Entry Point type (2.1 or 3.0)",
+    },
+    { /* end of list */ }
+};
+
 static const QemuOptDesc qemu_smbios_type0_opts[] = {
     {
         .name = "type",
@@ -797,7 +807,9 @@ void smbios_set_defaults(const char *manufacturer, const 
char *product,
     smbios_have_defaults = true;
     smbios_legacy = legacy_mode;
     smbios_uuid_encoded = uuid_encoded;
-    smbios_ep_type = ep_type;
+    if (!smbios_ep_type_set) {
+        smbios_ep_type = ep_type;
+    }
 
     /* drop unwanted version of command-line file blob(s) */
     if (smbios_legacy) {
@@ -1232,5 +1244,28 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
         }
     }
 
-    error_setg(errp, "Must specify type= or file=");
+    val = qemu_opt_get(opts, "entry-point-type");
+    if (val) {
+        if (!qemu_opts_validate(opts, qemu_smbios_entry_point_opts, errp)) {
+            return;
+        }
+
+        if (smbios_ep_type_set) {
+            error_setg(errp, "entry-point-type can't be set twice");
+            return;
+        }
+
+        if (!strcmp(val, "2.1")) {
+            smbios_ep_type = SMBIOS_ENTRY_POINT_21;
+            smbios_ep_type_set = true;
+        } else if (!strcmp(val, "3.0")) {
+            smbios_ep_type = SMBIOS_ENTRY_POINT_30;
+            smbios_ep_type_set = true;
+        } else {
+            error_setg(errp, "Invalid entry point type: %s", val);
+        }
+        return;
+    }
+
+    error_setg(errp, "Must specify type=, file=, or entry-point-type=");
 }
diff --git a/qemu-options.hx b/qemu-options.hx
index 104632ea34..d2a973f8a7 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2294,7 +2294,9 @@ DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
     "                specify SMBIOS type 11 fields\n"
     "-smbios 
type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
     "               [,asset=str][,part=str][,speed=%d]\n"
-    "                specify SMBIOS type 17 fields\n",
+    "                specify SMBIOS type 17 fields\n"
+    "-smbios entry-point-type=2.1|3.0\n"
+    "                specify SMBIOS entry point type\n",
     QEMU_ARCH_I386 | QEMU_ARCH_ARM)
 SRST
 ``-smbios file=binary``
@@ -2356,6 +2358,18 @@ SRST
 
 ``-smbios 
type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
     Specify SMBIOS type 17 fields
+
+``-smbios entry-point-type=2.1|3.0``
+    Specify SMBIOS entry point type
+
+    SMBIOS 3.0 allows the total size of SMBIOS tables to be much
+    larger, but note that Seabios for x86 does not support SMBIOS
+    3.0 (as of Seabios v1.14.0).
+
+    Note that this option only affects the SMBIOS data exposed
+    through fw_cfg.  It's still up to the firmware to generate
+    the actual SMBIOS entry point(s) seen by the guest operating
+    system.
 ERST
 
 DEFHEADING()
-- 
2.28.0