[RFC PATCH 10/13] vfio/pci: introduce command-line parameters to specify migration method

[Lei Rao]

Add command-line parameters (x-plugin-path and x-plugin-arg) of migration plugin
for VFIO PCI functions. x-plugin-path indicates the path of a dynamic load
library and x-plugin-arg is the necessary parameter to load and use it.
A typical example is, if the plugin communicates with the agent running on
IPU/DPU backend SOC through network, the argument should be the IP and Port of
agent. The usage as follows:

-device vfio-pci,id=$ID,host=$bdf,x-enable-migration,\
x-plugin-path=$plugin_path,x-plugin-arg=<IP:Port>

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
---
 hw/vfio/pci.c                 | 2 ++
 include/hw/vfio/vfio-common.h | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 939dcc3d4a..1553ba7116 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3309,6 +3309,8 @@ static Property vfio_pci_dev_properties[] = {
                                    qdev_prop_nv_gpudirect_clique, uint8_t),
     DEFINE_PROP_OFF_AUTO_PCIBAR("x-msix-relocation", VFIOPCIDevice, msix_relo,
                                 OFF_AUTOPCIBAR_OFF),
+    DEFINE_PROP_STRING("x-plugin-path", VFIOPCIDevice, vbasedev.desc.path),
+    DEFINE_PROP_STRING("x-plugin-arg", VFIOPCIDevice, vbasedev.desc.arg),
     /*
      * TODO - support passed fds... is this necessary?
      * DEFINE_PROP_STRING("vfiofd", VFIOPCIDevice, vfiofd_name),
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index be8adf890f..45d6d75284 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -58,6 +58,11 @@ typedef struct VFIORegion {
     uint8_t nr; /* cache the region number for debug */
 } VFIORegion;
 
+struct vfio_migration_plugin_desc {
+    char *path;
+    char *arg;
+};
+
 typedef struct VFIOMigrationOps VFIOMigrationOps;
 
 typedef struct VFIOMigration {
@@ -144,6 +149,7 @@ typedef struct VFIODevice {
     unsigned int num_regions;
     unsigned int flags;
     VFIOMigration *migration;
+    struct vfio_migration_plugin_desc desc;
     Error *migration_blocker;
     OnOffAuto pre_copy_dirty_page_tracking;
 } VFIODevice;
-- 
2.32.0