1 files changed, 50 insertions, 13 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 15812e553b95..0d83f25ac8ac 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -613,8 +613,8 @@ int xen_alloc_p2m_entry(unsigned long pfn)
 	}
 
 	/* Expanded the p2m? */
-	if (pfn > xen_p2m_last_pfn) {
-		xen_p2m_last_pfn = pfn;
+	if (pfn >= xen_p2m_last_pfn) {
+		xen_p2m_last_pfn = ALIGN(pfn + 1, P2M_PER_PAGE);
 		HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
 	}
 
@@ -706,9 +706,12 @@ 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)
+		if (map_ops[i].status != GNTST_okay ||
+		    (kmap_ops && kmap_ops[i].status != GNTST_okay))
 			continue;
 
 		if (map_ops[i].flags & GNTMAP_contains_pte) {
@@ -722,10 +725,46 @@ 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:
@@ -746,17 +785,15 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 		unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
 		unsigned long pfn = page_to_pfn(pages[i]);
 
-		if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
+		if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT))
+			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+		else
 			ret = -EINVAL;
-			goto out;
-		}
-
-		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 	}
 	if (kunmap_ops)
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
-						kunmap_ops, count);
-out:
+						kunmap_ops, count) ?: ret;
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);