hw/smbios: Add table 4 parameter, "processor-id"

This parameter is to be used in the processor_id entry in the type 4
table.

This parameter is set as optional and if left will use the values from
the CPU model.

This enables hiding the host information from the guest and allowing AMD
VMs to run pretending to be Intel for some userspace software concerns.

Reviewed-by: Peter Foley <pefoley@google.com>
Reviewed-by: Titus Rwantare <titusr@google.com>
Signed-off-by: Patrick Venture <venture@google.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20220125163118.1011809-1-venture@google.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
index 1f8d5c2..60349ee 100644
--- a/hw/smbios/smbios.c
+++ b/hw/smbios/smbios.c
@@ -104,9 +104,11 @@ static struct {
     const char *sock_pfx, *manufacturer, *version, *serial, *asset, *part;
     uint64_t max_speed;
     uint64_t current_speed;
+    uint64_t processor_id;
 } type4 = {
     .max_speed = DEFAULT_CPU_SPEED,
-    .current_speed = DEFAULT_CPU_SPEED
+    .current_speed = DEFAULT_CPU_SPEED,
+    .processor_id = 0,
 };
 
 static struct {
@@ -327,6 +329,10 @@ static const QemuOptDesc qemu_smbios_type4_opts[] = {
         .name = "part",
         .type = QEMU_OPT_STRING,
         .help = "part number",
+    }, {
+        .name = "processor-id",
+        .type = QEMU_OPT_NUMBER,
+        .help = "processor id",
     },
     { /* end of list */ }
 };
@@ -683,8 +689,13 @@ static void smbios_build_type_4_table(MachineState *ms, unsigned instance)
     t->processor_type = 0x03; /* CPU */
     t->processor_family = 0x01; /* Other */
     SMBIOS_TABLE_SET_STR(4, processor_manufacturer_str, type4.manufacturer);
-    t->processor_id[0] = cpu_to_le32(smbios_cpuid_version);
-    t->processor_id[1] = cpu_to_le32(smbios_cpuid_features);
+    if (type4.processor_id == 0) {
+        t->processor_id[0] = cpu_to_le32(smbios_cpuid_version);
+        t->processor_id[1] = cpu_to_le32(smbios_cpuid_features);
+    } else {
+        t->processor_id[0] = cpu_to_le32((uint32_t)type4.processor_id);
+        t->processor_id[1] = cpu_to_le32(type4.processor_id >> 32);
+    }
     SMBIOS_TABLE_SET_STR(4, processor_version_str, type4.version);
     t->voltage = 0;
     t->external_clock = cpu_to_le16(0); /* Unknown */
@@ -1323,6 +1334,8 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
             save_opt(&type4.serial, opts, "serial");
             save_opt(&type4.asset, opts, "asset");
             save_opt(&type4.part, opts, "part");
+            /* If the value is 0, it will take the value from the CPU model. */
+            type4.processor_id = qemu_opt_get_number(opts, "processor-id", 0);
             type4.max_speed = qemu_opt_get_number(opts, "max-speed",
                                                   DEFAULT_CPU_SPEED);
             type4.current_speed = qemu_opt_get_number(opts, "current-speed",