[PULL 23/28] vfio: implement unmap all for DMA unmap callbacks

["Cédric Le Goater" <clg@redhat.com>]

From: John Levon <john.levon@nutanix.com>

Handle unmap_all in the DMA unmap handlers rather than in the caller.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250507152020.1254632-10-john.levon@nutanix.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/container.c | 41 +++++++++++++++++++++++++++++++----------
 hw/vfio/iommufd.c   | 15 ++++++++++++++-
 hw/vfio/listener.c  | 19 ++++++-------------
 3 files changed, 51 insertions(+), 24 deletions(-)

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index d5f4e66f1c4146c2eb6a2ce209c74c4d391c27ce..a9f0dbaec4c8d83450048d9bc53b34d859731ebb 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -119,12 +119,9 @@ unmap_exit:
     return ret;
 }
 
-/*
- * DMA - Mapping and unmapping for the "type1" IOMMU interface used on x86
- */
-static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
-                                 hwaddr iova, ram_addr_t size,
-                                 IOMMUTLBEntry *iotlb, bool unmap_all)
+static int vfio_legacy_dma_unmap_one(const VFIOContainerBase *bcontainer,
+                                     hwaddr iova, ram_addr_t size,
+                                     IOMMUTLBEntry *iotlb)
 {
     const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
                                                   bcontainer);
@@ -138,10 +135,6 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
     int ret;
     Error *local_err = NULL;
 
-    if (unmap_all) {
-        return -ENOTSUP;
-    }
-
     if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
         if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
             bcontainer->dirty_pages_supported) {
@@ -185,6 +178,34 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
     return 0;
 }
 
+/*
+ * DMA - Mapping and unmapping for the "type1" IOMMU interface used on x86
+ */
+static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
+                                 hwaddr iova, ram_addr_t size,
+                                 IOMMUTLBEntry *iotlb, bool unmap_all)
+{
+    int ret;
+
+    if (unmap_all) {
+        /* The unmap ioctl doesn't accept a full 64-bit span. */
+        Int128 llsize = int128_rshift(int128_2_64(), 1);
+
+        ret = vfio_legacy_dma_unmap_one(bcontainer, 0, int128_get64(llsize),
+                                        iotlb);
+
+        if (ret == 0) {
+            ret = vfio_legacy_dma_unmap_one(bcontainer, int128_get64(llsize),
+                                            int128_get64(llsize), iotlb);
+        }
+
+    } else {
+        ret = vfio_legacy_dma_unmap_one(bcontainer, iova, size, iotlb);
+    }
+
+    return ret;
+}
+
 static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
                                ram_addr_t size, void *vaddr, bool readonly)
 {
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 6b2764c044135b95c199b5df2f864156817fb6fc..af1c7ab10a090a2a4a2913231fc50903be9fb0f1 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -51,8 +51,21 @@ static int iommufd_cdev_unmap(const VFIOContainerBase *bcontainer,
     const VFIOIOMMUFDContainer *container =
         container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);
 
+    /* unmap in halves */
     if (unmap_all) {
-        return -ENOTSUP;
+        Int128 llsize = int128_rshift(int128_2_64(), 1);
+        int ret;
+
+        ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
+                                        0, int128_get64(llsize));
+
+        if (ret == 0) {
+            ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
+                                            int128_get64(llsize),
+                                            int128_get64(llsize));
+        }
+
+        return ret;
     }
 
     /* TODO: Handle dma_unmap_bitmap with iotlb args (migration) */
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index c5183700dbd859c9a66083f2cb6f74a75a01cc66..e7ade7d62ec81c9228e096ba4818a8dd09f54bd3 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -634,21 +634,14 @@ static void vfio_listener_region_del(MemoryListener *listener,
     }
 
     if (try_unmap) {
+        bool unmap_all = false;
+
         if (int128_eq(llsize, int128_2_64())) {
-            /* The unmap ioctl doesn't accept a full 64-bit span. */
-            llsize = int128_rshift(llsize, 1);
-            ret = vfio_container_dma_unmap(bcontainer, iova,
-                                           int128_get64(llsize), NULL, false);
-            if (ret) {
-                error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
-                             "0x%"HWADDR_PRIx") = %d (%s)",
-                             bcontainer, iova, int128_get64(llsize), ret,
-                             strerror(-ret));
-            }
-            iova += int128_get64(llsize);
+            unmap_all = true;
+            llsize = int128_zero();
         }
-        ret = vfio_container_dma_unmap(bcontainer, iova,
-                                       int128_get64(llsize), NULL, false);
+        ret = vfio_container_dma_unmap(bcontainer, iova, int128_get64(llsize),
+                                       NULL, unmap_all);
         if (ret) {
             error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%s)",
-- 
2.49.0