[PATCH v27 12/17] vfio: Add function to start and stop dirty pages tracking

[Kirti Wankhede <kwankhede@nvidia.com>]

Call VFIO_IOMMU_DIRTY_PAGES ioctl to start and stop dirty pages tracking
for VFIO devices.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hw/vfio/migration.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index ea5e0f1b8489..77ee60a43ea5 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -11,6 +11,7 @@
 #include "qemu/main-loop.h"
 #include "qemu/cutils.h"
 #include <linux/vfio.h>
+#include <sys/ioctl.h>
 
 #include "sysemu/runstate.h"
 #include "hw/vfio/vfio-common.h"
@@ -391,6 +392,34 @@ static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
     return qemu_file_get_error(f);
 }
 
+static int vfio_set_dirty_page_tracking(VFIODevice *vbasedev, bool start)
+{
+    int ret;
+    VFIOMigration *migration = vbasedev->migration;
+    VFIOContainer *container = vbasedev->group->container;
+    struct vfio_iommu_type1_dirty_bitmap dirty = {
+        .argsz = sizeof(dirty),
+    };
+
+    if (start) {
+        if (migration->device_state & VFIO_DEVICE_STATE_SAVING) {
+            dirty.flags = VFIO_IOMMU_DIRTY_PAGES_FLAG_START;
+        } else {
+            return -EINVAL;
+        }
+    } else {
+            dirty.flags = VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP;
+    }
+
+    ret = ioctl(container->fd, VFIO_IOMMU_DIRTY_PAGES, &dirty);
+    if (ret) {
+        error_report("Failed to set dirty tracking flag 0x%x errno: %d",
+                     dirty.flags, errno);
+        return -errno;
+    }
+    return ret;
+}
+
 /* ---------------------------------------------------------------------- */
 
 static int vfio_save_setup(QEMUFile *f, void *opaque)
@@ -426,6 +455,11 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
         return ret;
     }
 
+    ret = vfio_set_dirty_page_tracking(vbasedev, true);
+    if (ret) {
+        return ret;
+    }
+
     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 
     ret = qemu_file_get_error(f);
@@ -441,6 +475,8 @@ static void vfio_save_cleanup(void *opaque)
     VFIODevice *vbasedev = opaque;
     VFIOMigration *migration = vbasedev->migration;
 
+    vfio_set_dirty_page_tracking(vbasedev, false);
+
     if (migration->region.mmaps) {
         vfio_region_unmap(&migration->region);
     }
-- 
2.7.0