vfio/common: Extract out vfio_kvm_device_[add/del]_fd

Introduce two new helpers, vfio_kvm_device_[add/del]_fd
which take as input a file descriptor which can be either a group fd or
a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
which aliases to the legacy KVM_DEV_VFIO_GROUP.

vfio_kvm_device_[add/del]_group then call those new helpers.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/common.c

@@ -1818,17 +1818,17 @@ void vfio_reset_handler(void *opaque)
     }
 }
 
-static void vfio_kvm_device_add_group(VFIOGroup *group)
+int vfio_kvm_device_add_fd(int fd, Error **errp)
 {
 #ifdef CONFIG_KVM
     struct kvm_device_attr attr = {
-        .group = KVM_DEV_VFIO_GROUP,
+        .group = KVM_DEV_VFIO_FILE,
-        .attr = KVM_DEV_VFIO_GROUP_ADD,
+        .attr = KVM_DEV_VFIO_FILE_ADD,
-        .addr = (uint64_t)(unsigned long)&group->fd,
+        .addr = (uint64_t)(unsigned long)&fd,
     };
 
     if (!kvm_enabled()) {
-        return;
+        return 0;
     }
 
     if (vfio_kvm_device_fd < 0) {
@@ -1837,38 +1837,61 @@ static void vfio_kvm_device_add_group(VFIOGroup *group)
         };
 
         if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
-            error_report("Failed to create KVM VFIO device: %m");
+            error_setg_errno(errp, errno, "Failed to create KVM VFIO device");
-            return;
+            return -errno;
         }
 
         vfio_kvm_device_fd = cd.fd;
     }
 
     if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
-        error_report("Failed to add group %d to KVM VFIO device: %m",
+        error_setg_errno(errp, errno, "Failed to add fd %d to KVM VFIO device",
-                     group->groupid);
+                         fd);
+        return -errno;
     }
 #endif
+    return 0;
+}
+
+int vfio_kvm_device_del_fd(int fd, Error **errp)
+{
+#ifdef CONFIG_KVM
+    struct kvm_device_attr attr = {
+        .group = KVM_DEV_VFIO_FILE,
+        .attr = KVM_DEV_VFIO_FILE_DEL,
+        .addr = (uint64_t)(unsigned long)&fd,
+    };
+
+    if (vfio_kvm_device_fd < 0) {
+        error_setg(errp, "KVM VFIO device isn't created yet");
+        return -EINVAL;
+    }
+
+    if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
+        error_setg_errno(errp, errno,
+                         "Failed to remove fd %d from KVM VFIO device", fd);
+        return -errno;
+    }
+#endif
+    return 0;
+}
+
+static void vfio_kvm_device_add_group(VFIOGroup *group)
+{
+    Error *err = NULL;
+
+    if (vfio_kvm_device_add_fd(group->fd, &err)) {
+        error_reportf_err(err, "group ID %d: ", group->groupid);
+    }
 }
 
 static void vfio_kvm_device_del_group(VFIOGroup *group)
 {
-#ifdef CONFIG_KVM
+    Error *err = NULL;
-    struct kvm_device_attr attr = {
-        .group = KVM_DEV_VFIO_GROUP,
-        .attr = KVM_DEV_VFIO_GROUP_DEL,
-        .addr = (uint64_t)(unsigned long)&group->fd,
-    };
 
-    if (vfio_kvm_device_fd < 0) {
+    if (vfio_kvm_device_del_fd(group->fd, &err)) {
-        return;
+        error_reportf_err(err, "group ID %d: ", group->groupid);
     }
-
-    if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
-        error_report("Failed to remove group %d from KVM VFIO device: %m",
-                     group->groupid);
-    }
-#endif
 }
 
 static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)

include/hw/vfio/vfio-common.h

@@ -226,6 +226,9 @@ struct vfio_device_info *vfio_get_device_info(int fd);
 int vfio_get_device(VFIOGroup *group, const char *name,
                     VFIODevice *vbasedev, Error **errp);
 
+int vfio_kvm_device_add_fd(int fd, Error **errp);
+int vfio_kvm_device_del_fd(int fd, Error **errp);
+
 extern const MemoryRegionOps vfio_region_ops;
 typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
 extern VFIOGroupList vfio_group_list;