[PATCH v2 10/20] vfio/common: Record DMA mapped IOVA ranges

[Avihai Horon]

From: Joao Martins <joao.m.martins@oracle.com>

According to the device DMA logging uAPI, IOVA ranges to be logged by
the device must be provided all at once upon DMA logging start.

As preparation for the following patches which will add device dirty
page tracking, keep a record of all DMA mapped IOVA ranges so later they
can be used for DMA logging start.

Note that when vIOMMU is enabled DMA mapped IOVA ranges are not tracked.
This is due to the dynamic nature of vIOMMU DMA mapping/unmapping.
Following patches will address the vIOMMU case specifically.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
---
 include/hw/vfio/vfio-common.h |  3 ++
 hw/vfio/common.c              | 86 +++++++++++++++++++++++++++++++++--
 2 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index ee55d442b4..6f36876ce0 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -23,6 +23,7 @@
 
 #include "exec/memory.h"
 #include "qemu/queue.h"
+#include "qemu/iova-tree.h"
 #include "qemu/notify.h"
 #include "ui/console.h"
 #include "hw/display/ramfb.h"
@@ -92,6 +93,8 @@ typedef struct VFIOContainer {
     uint64_t max_dirty_bitmap_size;
     unsigned long pgsizes;
     unsigned int dma_max_mappings;
+    IOVATree *mappings;
+    QemuMutex mappings_mutex;
     QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
     QLIST_HEAD(, VFIOHostDMAWindow) hostwin_list;
     QLIST_HEAD(, VFIOGroup) group_list;
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 84f08bdbbb..6041da6c7e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -44,6 +44,7 @@
 #include "migration/blocker.h"
 #include "migration/qemu-file.h"
 #include "sysemu/tpm.h"
+#include "qemu/iova-tree.h"
 
 VFIOGroupList vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -426,6 +427,11 @@ void vfio_unblock_multiple_devices_migration(void)
     multiple_devices_migration_blocker = NULL;
 }
 
+static bool vfio_have_giommu(VFIOContainer *container)
+{
+    return !QLIST_EMPTY(&container->giommu_list);
+}
+
 static void vfio_set_migration_error(int err)
 {
     MigrationState *ms = migrate_get_current();
@@ -499,6 +505,51 @@ static bool 
vfio_devices_all_running_and_mig_active(VFIOContainer *container)
     return true;
 }
 
+static int vfio_record_mapping(VFIOContainer *container, hwaddr iova,
+                               hwaddr size, bool readonly)
+{
+    DMAMap map = {
+        .iova = iova,
+        .size = size - 1, /* IOVATree is inclusive, so subtract 1 from size */
+        .perm = readonly ? IOMMU_RO : IOMMU_RW,
+    };
+    int ret;
+
+    if (vfio_have_giommu(container)) {
+        return 0;
+    }
+
+    WITH_QEMU_LOCK_GUARD(&container->mappings_mutex) {
+        ret = iova_tree_insert(container->mappings, &map);
+        if (ret) {
+            if (ret == IOVA_ERR_INVALID) {
+                ret = -EINVAL;
+            } else if (ret == IOVA_ERR_OVERLAP) {
+                ret = -EEXIST;
+            }
+        }
+    }
+
+    return ret;
+}
+
+static void vfio_erase_mapping(VFIOContainer *container, hwaddr iova,
+                                hwaddr size)
+{
+    DMAMap map = {
+        .iova = iova,
+        .size = size - 1, /* IOVATree is inclusive, so subtract 1 from size */
+    };
+
+    if (vfio_have_giommu(container)) {
+        return;
+    }
+
+    WITH_QEMU_LOCK_GUARD(&container->mappings_mutex) {
+        iova_tree_remove(container->mappings, map);
+    }
+}
+
 static int vfio_dma_unmap_bitmap(VFIOContainer *container,
                                  hwaddr iova, ram_addr_t size,
                                  IOMMUTLBEntry *iotlb)
@@ -599,6 +650,8 @@ static int vfio_dma_unmap(VFIOContainer *container,
                                             DIRTY_CLIENTS_NOCODE);
     }
 
+    vfio_erase_mapping(container, iova, size);
+
     return 0;
 }
 
@@ -612,6 +665,16 @@ static int vfio_dma_map(VFIOContainer *container, hwaddr 
iova,
         .iova = iova,
         .size = size,
     };
+    int ret;
+
+    ret = vfio_record_mapping(container, iova, size, readonly);
+    if (ret) {
+        error_report("vfio: Failed to record mapping, iova: 0x%" HWADDR_PRIx
+                     ", size: 0x" RAM_ADDR_FMT ", ret: %d (%s)",
+                     iova, size, ret, strerror(-ret));
+
+        return ret;
+    }
 
     if (!readonly) {
         map.flags |= VFIO_DMA_MAP_FLAG_WRITE;
@@ -628,8 +691,12 @@ static int vfio_dma_map(VFIOContainer *container, hwaddr 
iova,
         return 0;
     }
 
+    ret = -errno;
     error_report("VFIO_MAP_DMA failed: %s", strerror(errno));
-    return -errno;
+
+    vfio_erase_mapping(container, iova, size);
+
+    return ret;
 }
 
 static void vfio_host_win_add(VFIOContainer *container,
@@ -2183,16 +2250,23 @@ static int vfio_connect_container(VFIOGroup *group, 
AddressSpace *as,
     QLIST_INIT(&container->giommu_list);
     QLIST_INIT(&container->hostwin_list);
     QLIST_INIT(&container->vrdl_list);
+    container->mappings = iova_tree_new();
+    if (!container->mappings) {
+        error_setg(errp, "Cannot allocate DMA mappings tree");
+        ret = -ENOMEM;
+        goto free_container_exit;
+    }
+    qemu_mutex_init(&container->mappings_mutex);
 
     ret = vfio_init_container(container, group->fd, errp);
     if (ret) {
-        goto free_container_exit;
+        goto destroy_mappings_exit;
     }
 
     ret = vfio_ram_block_discard_disable(container, true);
     if (ret) {
         error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken");
-        goto free_container_exit;
+        goto destroy_mappings_exit;
     }
 
     switch (container->iommu_type) {
@@ -2328,6 +2402,10 @@ listener_release_exit:
 enable_discards_exit:
     vfio_ram_block_discard_disable(container, false);
 
+destroy_mappings_exit:
+    qemu_mutex_destroy(&container->mappings_mutex);
+    iova_tree_destroy(container->mappings);
+
 free_container_exit:
     g_free(container);
 
@@ -2382,6 +2460,8 @@ static void vfio_disconnect_container(VFIOGroup *group)
         }
 
         trace_vfio_disconnect_container(container->fd);
+        qemu_mutex_destroy(&container->mappings_mutex);
+        iova_tree_destroy(container->mappings);
         close(container->fd);
         g_free(container);
 
-- 
2.26.3