vfio: Add function to unmap VFIO region

This function will be used for migration region.
Migration region is mmaped when migration starts and will be unmapped when
migration is complete.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

hw/vfio/common.c

@@ -924,6 +924,18 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
     return 0;
 }
 
+static void vfio_subregion_unmap(VFIORegion *region, int index)
+{
+    trace_vfio_region_unmap(memory_region_name(&region->mmaps[index].mem),
+                            region->mmaps[index].offset,
+                            region->mmaps[index].offset +
+                            region->mmaps[index].size - 1);
+    memory_region_del_subregion(region->mem, &region->mmaps[index].mem);
+    munmap(region->mmaps[index].mmap, region->mmaps[index].size);
+    object_unparent(OBJECT(&region->mmaps[index].mem));
+    region->mmaps[index].mmap = NULL;
+}
+
 int vfio_region_mmap(VFIORegion *region)
 {
     int i, prot = 0;
@@ -954,10 +966,7 @@ int vfio_region_mmap(VFIORegion *region)
             region->mmaps[i].mmap = NULL;
 
             for (i--; i >= 0; i--) {
-                memory_region_del_subregion(region->mem, &region->mmaps[i].mem);
+                vfio_subregion_unmap(region, i);
-                munmap(region->mmaps[i].mmap, region->mmaps[i].size);
-                object_unparent(OBJECT(&region->mmaps[i].mem));
-                region->mmaps[i].mmap = NULL;
             }
 
             return ret;
@@ -982,6 +991,21 @@ int vfio_region_mmap(VFIORegion *region)
     return 0;
 }
 
+void vfio_region_unmap(VFIORegion *region)
+{
+    int i;
+
+    if (!region->mem) {
+        return;
+    }
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        if (region->mmaps[i].mmap) {
+            vfio_subregion_unmap(region, i);
+        }
+    }
+}
+
 void vfio_region_exit(VFIORegion *region)
 {
     int i;

hw/vfio/trace-events

@@ -113,6 +113,7 @@ vfio_region_mmap(const char *name, unsigned long offset, unsigned long end) "Reg
 vfio_region_exit(const char *name, int index) "Device %s, region %d"
 vfio_region_finalize(const char *name, int index) "Device %s, region %d"
 vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s mmaps enabled: %d"
+vfio_region_unmap(const char *name, unsigned long offset, unsigned long end) "Region %s unmap [0x%lx - 0x%lx]"
 vfio_region_sparse_mmap_header(const char *name, int index, int nr_areas) "Device %s region %d: %d sparse mmap entries"
 vfio_region_sparse_mmap_entry(int i, unsigned long start, unsigned long end) "sparse entry %d [0x%lx - 0x%lx]"
 vfio_get_dev_region(const char *name, int index, uint32_t type, uint32_t subtype) "%s index %d, %08x/%0x8"

include/hw/vfio/vfio-common.h

@@ -171,6 +171,7 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
                       int index, const char *name);
 int vfio_region_mmap(VFIORegion *region);
 void vfio_region_mmaps_set_enabled(VFIORegion *region, bool enabled);
+void vfio_region_unmap(VFIORegion *region);
 void vfio_region_exit(VFIORegion *region);
 void vfio_region_finalize(VFIORegion *region);
 void vfio_reset_handler(void *opaque);