pcie_sriov: Make a PCI device with user-created VF ARI-capable

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250314-sriov-v9-9-57dae8ae3ab5@daynix.com>
Tested-by: Yui Washizu <yui.washidu@gmail.com>
Tested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

docs/system/sriov.rst

@@ -28,7 +28,8 @@ virtio-net-pci functions to a bus. Below is a command line example:
 The VFs specify the paired PF with ``sriov-pf`` property. The PF must be
 added after all VFs. It is the user's responsibility to ensure that VFs have
 function numbers larger than one of the PF, and that the function numbers
-have a consistent stride.
+have a consistent stride. Both the PF and VFs are ARI-capable so you can have
+255 VFs at maximum.
 
 You may also need to perform additional steps to activate the SR-IOV feature on
 your guest. For Linux, refer to [1]_.

hw/pci/pcie_sriov.c

@@ -245,6 +245,7 @@ int16_t pcie_sriov_pf_init_from_user_created_vfs(PCIDevice *dev,
     PCIDevice **vfs;
     BusState *bus = qdev_get_parent_bus(DEVICE(dev));
     uint16_t ven_id = pci_get_word(dev->config + PCI_VENDOR_ID);
+    uint16_t size = PCI_EXT_CAP_SRIOV_SIZEOF;
     uint16_t vf_dev_id;
     uint16_t vf_offset;
     uint16_t vf_stride;
@@ -311,6 +312,11 @@ int16_t pcie_sriov_pf_init_from_user_created_vfs(PCIDevice *dev,
         return -1;
     }
 
+    if (!pcie_find_capability(dev, PCI_EXT_CAP_ID_ARI)) {
+        pcie_ari_init(dev, offset + size);
+        size += PCI_ARI_SIZEOF;
+    }
+
     for (i = 0; i < pf->len; i++) {
         vfs[i]->exp.sriov_vf.pf = dev;
         vfs[i]->exp.sriov_vf.vf_number = i;
@@ -331,7 +337,7 @@ int16_t pcie_sriov_pf_init_from_user_created_vfs(PCIDevice *dev,
         }
     }
 
-    return PCI_EXT_CAP_SRIOV_SIZEOF;
+    return size;
 }
 
 bool pcie_sriov_register_device(PCIDevice *dev, Error **errp)

hw/virtio/virtio-pci.c

@@ -2111,12 +2111,16 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
                          PCI_BASE_ADDRESS_SPACE_IO, &proxy->bar);
     }
 
-    res = pcie_sriov_pf_init_from_user_created_vfs(&proxy->pci_dev,
-                                                   proxy->last_pcie_cap_offset,
-                                                   errp);
-    if (res > 0) {
-        proxy->last_pcie_cap_offset += res;
-        virtio_add_feature(&vdev->host_features, VIRTIO_F_SR_IOV);
+    if (pci_is_vf(&proxy->pci_dev)) {
+        pcie_ari_init(&proxy->pci_dev, proxy->last_pcie_cap_offset);
+        proxy->last_pcie_cap_offset += PCI_ARI_SIZEOF;
+    } else {
+        res = pcie_sriov_pf_init_from_user_created_vfs(
+            &proxy->pci_dev, proxy->last_pcie_cap_offset, errp);
+        if (res > 0) {
+            proxy->last_pcie_cap_offset += res;
+            virtio_add_feature(&vdev->host_features, VIRTIO_F_SR_IOV);
+        }
     }
 }
 

include/hw/pci/pcie_sriov.h

@@ -43,12 +43,15 @@ void pcie_sriov_vf_register_bar(PCIDevice *dev, int region_num,
 
 /**
  * pcie_sriov_pf_init_from_user_created_vfs() - Initialize PF with user-created
- *                                              VFs.
+ *                                              VFs, adding ARI to PF
  * @dev: A PCIe device being realized.
  * @offset: The offset of the SR-IOV capability.
  * @errp: pointer to Error*, to store an error if it happens.
  *
- * Return: The size of added capability. 0 if the user did not create VFs.
+ * Initializes a PF with user-created VFs, adding the ARI extended capability to
+ * the PF. The VFs should call pcie_ari_init() to form an ARI device.
+ *
+ * Return: The size of added capabilities. 0 if the user did not create VFs.
  *         -1 if failed.
  */
 int16_t pcie_sriov_pf_init_from_user_created_vfs(PCIDevice *dev,