[PULL 10/31] vfio: Introduce helper vfio_pci_from_vfio_device()

["Cédric Le Goater" <clg@redhat.com>]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

Introduce helper vfio_pci_from_vfio_device() to transform from VFIODevice
to VFIOPCIDevice, also to hide low level VFIO_DEVICE_TYPE_PCI type check.

Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250822064101.123526-5-zhenzhong.duan@intel.com
[ clg: Added documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/pci.h       | 12 ++++++++++++
 hw/vfio/container.c |  4 ++--
 hw/vfio/device.c    |  2 +-
 hw/vfio/iommufd.c   |  4 ++--
 hw/vfio/listener.c  |  4 ++--
 hw/vfio/pci.c       |  9 +++++++++
 6 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 923cf9c2f79d078546239bf67195d6ba8157265a..96144b6fdeb94dccf6c0beecf039a12b9845c59b 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -226,6 +226,18 @@ void vfio_pci_write_config(PCIDevice *pdev,
 uint64_t vfio_vga_read(void *opaque, hwaddr addr, unsigned size);
 void vfio_vga_write(void *opaque, hwaddr addr, uint64_t data, unsigned size);
 
+/**
+ * vfio_pci_from_vfio_device: Transform from VFIODevice to
+ * VFIOPCIDevice
+ *
+ * This function checks if the given @vbasedev is a VFIO PCI device.
+ * If it is, it returns the containing VFIOPCIDevice.
+ *
+ * @vbasedev: The VFIODevice to transform
+ *
+ * Return: The VFIOPCIDevice on success, NULL on failure.
+ */
+VFIOPCIDevice *vfio_pci_from_vfio_device(VFIODevice *vbasedev);
 void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev);
 bool vfio_opt_rom_in_denylist(VFIOPCIDevice *vdev);
 bool vfio_config_quirk_setup(VFIOPCIDevice *vdev, Error **errp);
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 3e13feaa74c30e8d7f5a0978e15824cecbf6d674..134ddccc52449cd7d4ac90d17075e9fca5439674 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -1087,7 +1087,7 @@ static int vfio_legacy_pci_hot_reset(VFIODevice *vbasedev, bool single)
         /* Prep dependent devices for reset and clear our marker. */
         QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
             if (!vbasedev_iter->dev->realized ||
-                vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
+                !vfio_pci_from_vfio_device(vbasedev_iter)) {
                 continue;
             }
             tmp = container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
@@ -1172,7 +1172,7 @@ out:
 
         QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
             if (!vbasedev_iter->dev->realized ||
-                vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
+                !vfio_pci_from_vfio_device(vbasedev_iter)) {
                 continue;
             }
             tmp = container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 52a1996dc4e122499a978cc8a5ce7e01620a9639..08f12ac31f44fdebc9fc1f23f716c52f391ed53e 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -129,7 +129,7 @@ static inline const char *action_to_str(int action)
 
 static const char *index_to_str(VFIODevice *vbasedev, int index)
 {
-    if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
+    if (!vfio_pci_from_vfio_device(vbasedev)) {
         return NULL;
     }
 
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 48c590b6a9467c8139131bef8b92864893a8f2e6..8c27222f754a22f47fda6b6a1a86005341ec0d7f 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -737,8 +737,8 @@ iommufd_cdev_dep_get_realized_vpdev(struct vfio_pci_dependent_device *dep_dev,
     }
 
     vbasedev_tmp = iommufd_cdev_pci_find_by_devid(dep_dev->devid);
-    if (!vbasedev_tmp || !vbasedev_tmp->dev->realized ||
-        vbasedev_tmp->type != VFIO_DEVICE_TYPE_PCI) {
+    if (!vfio_pci_from_vfio_device(vbasedev_tmp) ||
+        !vbasedev_tmp->dev->realized) {
         return NULL;
     }
 
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index c244be5e218ae60e2b9c8a29d2d4b9dad86fc77a..e0938331659833bdca98e700ac42651a90fb1571 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -453,7 +453,7 @@ static void vfio_device_error_append(VFIODevice *vbasedev, Error **errp)
      * MMIO region mapping failures are not fatal but in this case PCI
      * peer-to-peer transactions are broken.
      */
-    if (vbasedev && vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
+    if (vfio_pci_from_vfio_device(vbasedev)) {
         error_append_hint(errp, "%s: PCI peer-to-peer transactions "
                           "on BARs are not supported.\n", vbasedev->name);
     }
@@ -759,7 +759,7 @@ static bool vfio_section_is_vfio_pci(MemoryRegionSection *section,
     owner = memory_region_owner(section->mr);
 
     QLIST_FOREACH(vbasedev, &bcontainer->device_list, container_next) {
-        if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
+        if (!vfio_pci_from_vfio_device(vbasedev)) {
             continue;
         }
         pcidev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 07257d0fa049b09fc296ac2279a6fafbdf93d277..3fe5b03eb1160bb66fc4ae3942d14a2d71b4431a 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2833,6 +2833,15 @@ static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f)
     return ret;
 }
 
+/* Transform from VFIODevice to VFIOPCIDevice. Return NULL if fails. */
+VFIOPCIDevice *vfio_pci_from_vfio_device(VFIODevice *vbasedev)
+{
+    if (vbasedev && vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
+        return container_of(vbasedev, VFIOPCIDevice, vbasedev);
+    }
+    return NULL;
+}
+
 void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev)
 {
     PCIDevice *pdev = &vdev->pdev;
-- 
2.51.0