[PATCH v3 08/13] vfio/common: Add device dirty page tracking start/stop

[Joao Martins]

Add device dirty page tracking start/stop functionality. This uses the
device DMA logging uAPI to start and stop dirty page tracking by device.

Device dirty page tracking is used only if all devices within a
container support device dirty page tracking.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 hw/vfio/common.c              | 166 +++++++++++++++++++++++++++++++++-
 hw/vfio/trace-events          |   1 +
 include/hw/vfio/vfio-common.h |   2 +
 3 files changed, 166 insertions(+), 3 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index d84e5fd86bb4..aa0df0604704 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -453,6 +453,22 @@ static bool vfio_devices_all_dirty_tracking(VFIOContainer 
*container)
     return true;
 }
 
+static bool vfio_devices_all_device_dirty_tracking(VFIOContainer *container)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev;
+
+    QLIST_FOREACH(group, &container->group_list, container_next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            if (!vbasedev->dirty_pages_supported) {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
 /*
  * Check if all VFIO devices are running and migration is active, which is
  * essentially equivalent to the migration being in pre-copy phase.
@@ -1395,15 +1411,152 @@ static void vfio_dirty_tracking_init(VFIOContainer 
*container)
     qemu_mutex_destroy(&container->tracking_mutex);
 }
 
+static int vfio_devices_dma_logging_set(VFIOContainer *container,
+                                        struct vfio_device_feature *feature)
+{
+    bool status = (feature->flags & VFIO_DEVICE_FEATURE_MASK) ==
+                  VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
+    VFIODevice *vbasedev;
+    VFIOGroup *group;
+    int ret = 0;
+
+    QLIST_FOREACH(group, &container->group_list, container_next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            if (vbasedev->dirty_tracking == status) {
+                continue;
+            }
+
+            ret = ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
+            if (ret) {
+                ret = -errno;
+                error_report("%s: Failed to set DMA logging %s, err %d (%s)",
+                             vbasedev->name, status ? "start" : "stop", ret,
+                             strerror(errno));
+                goto out;
+            }
+            vbasedev->dirty_tracking = status;
+        }
+    }
+
+out:
+    return ret;
+}
+
+static int vfio_devices_dma_logging_stop(VFIOContainer *container)
+{
+    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature),
+                              sizeof(uint64_t))] = {};
+    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
+
+    feature->argsz = sizeof(buf);
+    feature->flags = VFIO_DEVICE_FEATURE_SET;
+    feature->flags |= VFIO_DEVICE_FEATURE_DMA_LOGGING_STOP;
+
+    return vfio_devices_dma_logging_set(container, feature);
+}
+
+static struct vfio_device_feature *
+vfio_device_feature_dma_logging_start_create(VFIOContainer *container)
+{
+    struct vfio_device_feature *feature;
+    size_t feature_size;
+    struct vfio_device_feature_dma_logging_control *control;
+    struct vfio_device_feature_dma_logging_range *ranges;
+    VFIODirtyTrackingRange *tracking = &container->tracking_range;
+
+    feature_size = sizeof(struct vfio_device_feature) +
+                   sizeof(struct vfio_device_feature_dma_logging_control);
+    feature = g_try_malloc0(feature_size);
+    if (!feature) {
+        errno = ENOMEM;
+        return NULL;
+    }
+    feature->argsz = feature_size;
+    feature->flags = VFIO_DEVICE_FEATURE_SET;
+    feature->flags |= VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
+
+    control = (struct vfio_device_feature_dma_logging_control *)feature->data;
+    control->page_size = qemu_real_host_page_size();
+
+    /*
+     * DMA logging uAPI guarantees to support at least a number of ranges that
+     * fits into a single host kernel base page.
+     */
+    control->num_ranges = !!tracking->max32 + !!tracking->max64;
+    ranges = g_try_new0(struct vfio_device_feature_dma_logging_range,
+                        control->num_ranges);
+    if (!ranges) {
+        g_free(feature);
+        errno = ENOMEM;
+
+        return NULL;
+    }
+
+    control->ranges = (__aligned_u64)ranges;
+    if (tracking->max32) {
+        ranges->iova = tracking->min32;
+        ranges->length = (tracking->max32 - tracking->min32) + 1;
+        ranges++;
+    }
+    if (tracking->max64) {
+        ranges->iova = tracking->min64;
+        ranges->length = (tracking->max64 - tracking->min64) + 1;
+    }
+
+    trace_vfio_device_dirty_tracking_start(control->num_ranges,
+                                           tracking->min32, tracking->max32,
+                                           tracking->min64, tracking->max64);
+
+    return feature;
+}
+
+static void vfio_device_feature_dma_logging_start_destroy(
+    struct vfio_device_feature *feature)
+{
+    struct vfio_device_feature_dma_logging_control *control =
+        (struct vfio_device_feature_dma_logging_control *)feature->data;
+    struct vfio_device_feature_dma_logging_range *ranges =
+        (struct vfio_device_feature_dma_logging_range *)control->ranges;
+
+    g_free(ranges);
+    g_free(feature);
+}
+
+static int vfio_devices_dma_logging_start(VFIOContainer *container)
+{
+    struct vfio_device_feature *feature;
+    int ret = 0;
+
+    vfio_dirty_tracking_init(container);
+    feature = vfio_device_feature_dma_logging_start_create(container);
+    if (!feature) {
+        return -errno;
+    }
+
+    ret = vfio_devices_dma_logging_set(container, feature);
+    if (ret) {
+        vfio_devices_dma_logging_stop(container);
+    }
+
+    vfio_device_feature_dma_logging_start_destroy(feature);
+
+    return ret;
+}
+
 static void vfio_listener_log_global_start(MemoryListener *listener)
 {
     VFIOContainer *container = container_of(listener, VFIOContainer, listener);
     int ret;
 
-    vfio_dirty_tracking_init(container);
+    if (vfio_devices_all_device_dirty_tracking(container)) {
+        ret = vfio_devices_dma_logging_start(container);
+    } else {
+        ret = vfio_set_dirty_page_tracking(container, true);
+    }
 
-    ret = vfio_set_dirty_page_tracking(container, true);
     if (ret) {
+        error_report("vfio: Could not start dirty page tracking, err: %d (%s)",
+                     ret, strerror(-ret));
         vfio_set_migration_error(ret);
     }
 }
@@ -1413,8 +1566,15 @@ static void vfio_listener_log_global_stop(MemoryListener 
*listener)
     VFIOContainer *container = container_of(listener, VFIOContainer, listener);
     int ret;
 
-    ret = vfio_set_dirty_page_tracking(container, false);
+    if (vfio_devices_all_device_dirty_tracking(container)) {
+        ret = vfio_devices_dma_logging_stop(container);
+    } else {
+        ret = vfio_set_dirty_page_tracking(container, false);
+    }
+
     if (ret) {
+        error_report("vfio: Could not stop dirty page tracking, err: %d (%s)",
+                     ret, strerror(-ret));
         vfio_set_migration_error(ret);
     }
 }
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index d97a6de17921..7a7e0cfe5b23 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -105,6 +105,7 @@ vfio_listener_region_add_no_dma_map(const char *name, 
uint64_t iova, uint64_t si
 vfio_listener_region_del_skip(uint64_t start, uint64_t end) "SKIPPING 
region_del 0x%"PRIx64" - 0x%"PRIx64
 vfio_listener_region_del(uint64_t start, uint64_t end) "region_del 0x%"PRIx64" 
- 0x%"PRIx64
 vfio_device_dirty_tracking_update(uint64_t start, uint64_t end, uint64_t min, 
uint64_t max) "section 0x%"PRIx64" - 0x%"PRIx64" -> update [0x%"PRIx64" - 
0x%"PRIx64"]"
+vfio_device_dirty_tracking_start(int nr_ranges, uint64_t min32, uint64_t 
max32, uint64_t min64, uint64_t max64) "nr_ranges %d 32:[0x%"PRIx64" - 
0x%"PRIx64"], 64:[0x%"PRIx64" - 0x%"PRIx64"]"
 vfio_disconnect_container(int fd) "close container->fd=%d"
 vfio_put_group(int fd) "close group->fd=%d"
 vfio_get_device(const char * name, unsigned int flags, unsigned int 
num_regions, unsigned int num_irqs) "Device %s flags: %u, regions: %u, irqs: %u"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 96791add2719..1cbbccd91e11 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -154,6 +154,8 @@ typedef struct VFIODevice {
     VFIOMigration *migration;
     Error *migration_blocker;
     OnOffAuto pre_copy_dirty_page_tracking;
+    bool dirty_pages_supported;
+    bool dirty_tracking;
 } VFIODevice;
 
 struct VFIODeviceOps {
-- 
2.17.2