[PATCH v2 2/2] hw/smbios: retrieve PCI address from specified device for Type 41

[Vincent Bernat <vincent@bernat.ch>]

Instead of specifying the PCI address manually, the device can be
specified by ID:

    $QEMU -netdev user,id=internet
          -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \
          -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev

The PCI segment is assumed to be 0. This should hold true for most
cases.

    $ dmidecode -t 41
    # dmidecode 3.3
    Getting SMBIOS data from sysfs.
    SMBIOS 2.8 present.

    Handle 0x2900, DMI type 41, 11 bytes
    Onboard Device
            Reference Designation: Onboard LAN
            Type: Ethernet
            Status: Enabled
            Type Instance: 1
            Bus Address: 0000:00:09.0

    $ ip -brief a
    lo               UNKNOWN        127.0.0.1/8 ::1/128
    eno1             UP             10.0.2.14/24 fec0::5254:ff:fe00:42/64 fe80::5254:ff:fe00:42/64

Signed-off-by: Vincent Bernat <vincent@bernat.ch>
---
 hw/smbios/smbios.c | 47 +++++++++++++++++++++-------------------------
 qemu-options.hx    |  2 +-
 2 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
index 46a08652dff4..0f390e03453c 100644
--- a/hw/smbios/smbios.c
+++ b/hw/smbios/smbios.c
@@ -27,6 +27,7 @@
 #include "hw/firmware/smbios.h"
 #include "hw/loader.h"
 #include "hw/boards.h"
+#include "hw/pci/pci.h"
 #include "smbios_build.h"
 
 /* legacy structures and constants for <= 2.0 machines */
@@ -134,12 +135,8 @@ static QEnumLookup type41_kind_lookup = {
     .size = 10
 };
 struct type41_instance {
-    const char *designation;
+    const char *designation, *pcidev;
     uint8_t instance, kind;
-    struct {
-        uint16_t segment;
-        uint8_t bus, device;
-    } pci;
     QTAILQ_ENTRY(type41_instance) next;
 };
 static QTAILQ_HEAD(, type41_instance) type41 = QTAILQ_HEAD_INITIALIZER(type41);
@@ -403,10 +400,9 @@ static const QemuOptDesc qemu_smbios_type41_opts[] = {
         .type = QEMU_OPT_NUMBER,
         .help = "device type instance",
     },{
-        .name = "pci",
+        .name = "pcidev",
         .type = QEMU_OPT_STRING,
         .help = "PCI device",
-        .def_value_str = "0:0.0",
     },
     { /* end of list */ }
 };
@@ -837,9 +833,23 @@ static void smbios_build_type_41_table(void)
         SMBIOS_TABLE_SET_STR(41, reference_designation_str, t41->designation);
         t->device_type = t41->kind;
         t->device_type_instance = t41->instance;
-        t->segment_group_number = cpu_to_le16(t41->pci.segment);
-        t->bus_number = t41->pci.bus;
-        t->device_number = t41->pci.device;
+
+        if (t41->pcidev) {
+            PCIDevice *pdev = NULL;
+            int rc = pci_qdev_find_device(t41->pcidev, &pdev);
+            if (rc == 0) {
+                /*
+                 * TODO: Extract the appropriate value. Most of the
+                 * time, this will be 0.
+                 */
+                t->segment_group_number = cpu_to_le16(0);
+                t->bus_number = pci_dev_bus_num(pdev);
+                t->device_number = pdev->devfn;
+            } else {
+                fprintf(stderr, "%s: cannot find PCI device %s\n",
+                        __func__, t41->pcidev);
+            }
+        }
 
         SMBIOS_BUILD_TABLE_POST;
         instance++;
@@ -1301,7 +1311,6 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
         case 41: {
             struct type41_instance *t;
             Error *local_err = NULL;
-            int pseg, pbus, pdevice, pfunction;
 
             if (!qemu_opts_validate(opts, qemu_smbios_type41_opts, errp)) {
                 return;
@@ -1324,21 +1333,7 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
                 return;
             }
             t->instance = qemu_opt_get_number(opts, "instance", 1);
-            if (sscanf(qemu_opt_get(opts, "pci"), "%x:%x:%x.%x",
-                       &pseg,
-                       &pbus,
-                       &pdevice,
-                       &pfunction) != 4) {
-                error_setg(errp, "unable to parse %s: %s",
-                           qemu_opt_get(opts, "pci"),
-                           g_strerror(errno));
-                free(t);
-                return;
-            }
-            t->pci.segment = pseg;
-            t->pci.bus = pbus;
-            t->pci.device = ((uint8_t)pdevice << 3) +
-                ((uint8_t)pfunction & 0x7);
+            save_opt(&t->pcidev, opts, "pcidev");
 
             QTAILQ_INSERT_TAIL(&type41, t, next);
             return;
diff --git a/qemu-options.hx b/qemu-options.hx
index eb2de7c372c7..e6e54f9bd1f3 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2371,7 +2371,7 @@ DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
     "-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"
-    "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pci=%x:%x:%x.%x]\n"
+    "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n"
     "                specify SMBIOS type 41 fields\n",
     QEMU_ARCH_I386 | QEMU_ARCH_ARM)
 SRST
-- 
2.31.0