[PULL 05/17] vfio/common: Add helper to validate iova/end against hostwin

[Alex Williamson <alex.williamson@redhat.com>]

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

Move the code that finds the container host DMA window against a iova
range. This avoids duplication on the common checks across listener
callbacks.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Avihai Horon <avihaih@nvidia.com>
Link: https://lore.kernel.org/r/20230307125450.62409-6-joao.m.martins@oracle.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/common.c |   38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index cec3de08d2b4..99acb998eb14 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -901,6 +901,22 @@ static void vfio_unregister_ram_discard_listener(VFIOContainer *container,
     g_free(vrdl);
 }
 
+static VFIOHostDMAWindow *vfio_find_hostwin(VFIOContainer *container,
+                                            hwaddr iova, hwaddr end)
+{
+    VFIOHostDMAWindow *hostwin;
+    bool hostwin_found = false;
+
+    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
+        if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
+            hostwin_found = true;
+            break;
+        }
+    }
+
+    return hostwin_found ? hostwin : NULL;
+}
+
 static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
 {
     MemoryRegion *mr = section->mr;
@@ -926,7 +942,6 @@ static void vfio_listener_region_add(MemoryListener *listener,
     void *vaddr;
     int ret;
     VFIOHostDMAWindow *hostwin;
-    bool hostwin_found;
     Error *err = NULL;
 
     if (vfio_listener_skipped_section(section)) {
@@ -1027,15 +1042,8 @@ static void vfio_listener_region_add(MemoryListener *listener,
 #endif
     }
 
-    hostwin_found = false;
-    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
-        if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
-            hostwin_found = true;
-            break;
-        }
-    }
-
-    if (!hostwin_found) {
+    hostwin = vfio_find_hostwin(container, iova, end);
+    if (!hostwin) {
         error_setg(&err, "Container %p can't map guest IOVA region"
                    " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx, container, iova, end);
         goto fail;
@@ -1237,15 +1245,9 @@ static void vfio_listener_region_del(MemoryListener *listener,
     if (memory_region_is_ram_device(section->mr)) {
         hwaddr pgmask;
         VFIOHostDMAWindow *hostwin;
-        bool hostwin_found = false;
 
-        QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
-            if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
-                hostwin_found = true;
-                break;
-            }
-        }
-        assert(hostwin_found); /* or region_add() would have failed */
+        hostwin = vfio_find_hostwin(container, iova, end);
+        assert(hostwin); /* or region_add() would have failed */
 
         pgmask = (1ULL << ctz64(hostwin->iova_pgsizes)) - 1;
         try_unmap = !((iova & pgmask) || (int128_get64(llsize) & pgmask));