diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index fd6e3aafe27241ad1a2a11f72fb51adc6fd4438f..acb464547a54f45d90a05437517ce14e5448f21a 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -93,12 +93,39 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 	int i;
 
 	for (i = 0; i < count; i++) {
+		struct gnttab_unmap_grant_ref unmap;
+		int rc;
+
 		if (map_ops[i].status)
 			continue;
-		if (unlikely(!set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
-				    map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT))) {
-			return -ENOMEM;
-		}
+		if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
+				    map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
+			continue;
+
+		/*
+		 * Signal an error for this slot. This in turn requires
+		 * immediate unmapping.
+		 */
+		map_ops[i].status = GNTST_general_error;
+		unmap.host_addr = map_ops[i].host_addr,
+		unmap.handle = map_ops[i].handle;
+		map_ops[i].handle = ~0;
+		if (map_ops[i].flags & GNTMAP_device_map)
+			unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
+		else
+			unmap.dev_bus_addr = 0;
+
+		/*
+		 * Pre-populate the status field, to be recognizable in
+		 * the log message below.
+		 */
+		unmap.status = 1;
+
+		rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+					       &unmap, 1);
+		if (rc || unmap.status != GNTST_okay)
+			pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
+				    rc, unmap.status);
 	}
 
 	return 0;
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index b5949e5a83ec8bb3f454bccdbe551c40416e2a8c..9545b8df531599f3d0e76737ec59dbb460f0c622 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -710,6 +710,8 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 
 	for (i = 0; i < count; i++) {
 		unsigned long mfn, pfn;
+		struct gnttab_unmap_grant_ref unmap[2];
+		int rc;
 
 		/* Do not add to override if the map failed. */
 		if (map_ops[i].status != GNTST_okay ||
@@ -727,10 +729,46 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 
 		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
 
-		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
-			ret = -ENOMEM;
-			goto out;
+		if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
+			continue;
+
+		/*
+		 * Signal an error for this slot. This in turn requires
+		 * immediate unmapping.
+		 */
+		map_ops[i].status = GNTST_general_error;
+		unmap[0].host_addr = map_ops[i].host_addr,
+		unmap[0].handle = map_ops[i].handle;
+		map_ops[i].handle = ~0;
+		if (map_ops[i].flags & GNTMAP_device_map)
+			unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr;
+		else
+			unmap[0].dev_bus_addr = 0;
+
+		if (kmap_ops) {
+			kmap_ops[i].status = GNTST_general_error;
+			unmap[1].host_addr = kmap_ops[i].host_addr,
+			unmap[1].handle = kmap_ops[i].handle;
+			kmap_ops[i].handle = ~0;
+			if (kmap_ops[i].flags & GNTMAP_device_map)
+				unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr;
+			else
+				unmap[1].dev_bus_addr = 0;
 		}
+
+		/*
+		 * Pre-populate both status fields, to be recognizable in
+		 * the log message below.
+		 */
+		unmap[0].status = 1;
+		unmap[1].status = 1;
+
+		rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+					       unmap, 1 + !!kmap_ops);
+		if (rc || unmap[0].status != GNTST_okay ||
+		    unmap[1].status != GNTST_okay)
+			pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n",
+				    rc, unmap[0].status, unmap[1].status);
 	}
 
 out: