virtio: get class_id and pci device id by the virtio id

Add helpers to get the "Transitional PCI Device ID" and "class_id"
of the device specified by the "Virtio Device ID".

These helpers will be used to build the generic vDPA device later.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Longpeng <longpeng2@huawei.com>
Message-Id: <20221215134944.2809-2-longpeng2@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio-pci.c

@@ -19,6 +19,7 @@
 
 #include "exec/memop.h"
 #include "standard-headers/linux/virtio_pci.h"
+#include "standard-headers/linux/virtio_ids.h"
 #include "hw/boards.h"
 #include "hw/virtio/virtio.h"
 #include "migration/qemu-file-types.h"
@@ -224,6 +225,90 @@ static int virtio_pci_load_queue(DeviceState *d, int n, QEMUFile *f)
     return 0;
 }
 
+typedef struct VirtIOPCIIDInfo {
+    /* virtio id */
+    uint16_t vdev_id;
+    /* pci device id for the transitional device */
+    uint16_t trans_devid;
+    uint16_t class_id;
+} VirtIOPCIIDInfo;
+
+static const VirtIOPCIIDInfo virtio_pci_id_info[] = {
+    {
+        .vdev_id = VIRTIO_ID_CRYPTO,
+        .class_id = PCI_CLASS_OTHERS,
+    }, {
+        .vdev_id = VIRTIO_ID_FS,
+        .class_id = PCI_CLASS_STORAGE_OTHER,
+    }, {
+        .vdev_id = VIRTIO_ID_NET,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_NET,
+        .class_id = PCI_CLASS_NETWORK_ETHERNET,
+    }, {
+        .vdev_id = VIRTIO_ID_BLOCK,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_BLOCK,
+        .class_id = PCI_CLASS_STORAGE_SCSI,
+    }, {
+        .vdev_id = VIRTIO_ID_CONSOLE,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_CONSOLE,
+        .class_id = PCI_CLASS_COMMUNICATION_OTHER,
+    }, {
+        .vdev_id = VIRTIO_ID_SCSI,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_SCSI,
+        .class_id = PCI_CLASS_STORAGE_SCSI
+    }, {
+        .vdev_id = VIRTIO_ID_9P,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_9P,
+        .class_id = PCI_BASE_CLASS_NETWORK,
+    }, {
+        .vdev_id = VIRTIO_ID_BALLOON,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_BALLOON,
+        .class_id = PCI_CLASS_OTHERS,
+    }, {
+        .vdev_id = VIRTIO_ID_RNG,
+        .trans_devid = PCI_DEVICE_ID_VIRTIO_RNG,
+        .class_id = PCI_CLASS_OTHERS,
+    },
+};
+
+static const VirtIOPCIIDInfo *virtio_pci_get_id_info(uint16_t vdev_id)
+{
+    const VirtIOPCIIDInfo *info = NULL;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(virtio_pci_id_info); i++) {
+        if (virtio_pci_id_info[i].vdev_id == vdev_id) {
+            info = &virtio_pci_id_info[i];
+            break;
+        }
+    }
+
+    if (!info) {
+        /* The device id is invalid or not added to the id_info yet. */
+        error_report("Invalid virtio device(id %u)", vdev_id);
+        abort();
+    }
+
+    return info;
+}
+
+/*
+ * Get the Transitional Device ID for the specific device, return
+ * zero if the device is non-transitional.
+ */
+uint16_t virtio_pci_get_trans_devid(uint16_t device_id)
+{
+    return virtio_pci_get_id_info(device_id)->trans_devid;
+}
+
+/*
+ * Get the Class ID for the specific device.
+ */
+uint16_t virtio_pci_get_class_id(uint16_t device_id)
+{
+    return virtio_pci_get_id_info(device_id)->class_id;
+}
+
 static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
 {
     VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
@@ -1729,6 +1814,9 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
          * is set to PCI_SUBVENDOR_ID_REDHAT_QUMRANET by default.
          */
         pci_set_word(config + PCI_SUBSYSTEM_ID, virtio_bus_get_vdev_id(bus));
+        if (proxy->trans_devid) {
+            pci_config_set_device_id(config, proxy->trans_devid);
+        }
     } else {
         /* pure virtio-1.0 */
         pci_set_word(config + PCI_VENDOR_ID,

include/hw/virtio/virtio-pci.h

@@ -151,6 +151,8 @@ struct VirtIOPCIProxy {
     bool disable_modern;
     bool ignore_backend_features;
     OnOffAuto disable_legacy;
+    /* Transitional device id */
+    uint16_t trans_devid;
     uint32_t class_code;
     uint32_t nvectors;
     uint32_t dfselect;
@@ -184,6 +186,9 @@ static inline void virtio_pci_disable_modern(VirtIOPCIProxy *proxy)
     proxy->disable_modern = true;
 }
 
+uint16_t virtio_pci_get_trans_devid(uint16_t device_id);
+uint16_t virtio_pci_get_class_id(uint16_t device_id);
+
 /*
  * virtio-input-pci: This extends VirtioPCIProxy.
  */