[TPM] back: Allocate pages for foreign mappings individually rather than contiguously.

Signed-off-by: Keir Fraser <keir@xensource.com>

linux-2.6-xen-sparse/drivers/xen/tpmback/common.h

@@ -46,11 +46,10 @@ typedef struct tpmif_st {
 	atomic_t refcnt;
 
 	struct backend_info *bi;
-	unsigned long mmap_vstart;
 
 	grant_handle_t shmem_handle;
 	grant_ref_t shmem_ref;
-	struct page *pagerange;
+	struct page **mmap_pages;
 
 	char devname[20];
 } tpmif_t;
@@ -80,6 +79,9 @@ int vtpm_release_packets(tpmif_t * tpmif, int send_msgs);
 
 extern int num_frontends;
 
-#define MMAP_VADDR(t,_req) ((t)->mmap_vstart + ((_req) * PAGE_SIZE))
+static inline unsigned long idx_to_kaddr(tpmif_t *t, unsigned int idx)
+{
+	return (unsigned long)pfn_to_kaddr(page_to_pfn(t->mmap_pages[idx]));
+}
 
 #endif /* __TPMIF__BACKEND__COMMON_H__ */

linux-2.6-xen-sparse/drivers/xen/tpmback/interface.c

@@ -23,10 +23,11 @@ LIST_HEAD(tpmif_list);
 static tpmif_t *alloc_tpmif(domid_t domid, struct backend_info *bi)
 {
 	tpmif_t *tpmif;
+	int i;
 
 	tpmif = kmem_cache_alloc(tpmif_cachep, GFP_KERNEL);
 	if (!tpmif)
-		return ERR_PTR(-ENOMEM);
+		goto out_of_memory;
 
 	memset(tpmif, 0, sizeof (*tpmif));
 	tpmif->domid = domid;
@@ -35,22 +36,46 @@ static tpmif_t *alloc_tpmif(domid_t domid, struct backend_info *bi)
 	snprintf(tpmif->devname, sizeof(tpmif->devname), "tpmif%d", domid);
 	atomic_set(&tpmif->refcnt, 1);
 
-	tpmif->pagerange = balloon_alloc_empty_page_range(TPMIF_TX_RING_SIZE);
-	BUG_ON(tpmif->pagerange == NULL);
-	tpmif->mmap_vstart = (unsigned long)pfn_to_kaddr(
-	                                    page_to_pfn(tpmif->pagerange));
+	tpmif->mmap_pages = kmalloc(sizeof(tpmif->mmap_pages[0])
+				    * TPMIF_TX_RING_SIZE, GFP_KERNEL);
+	if (tpmif->mmap_pages == NULL)
+		goto out_of_memory;
+
+	for (i = 0; i < TPMIF_TX_RING_SIZE; i++) {
+		tpmif->mmap_pages[i] = balloon_alloc_empty_page();
+		if (tpmif->mmap_pages[i] == NULL) {
+			while (--i >= 0)
+				balloon_free_empty_page(tpmif->mmap_pages[i]);
+			goto out_of_memory;
+		}
+	}
 
 	list_add(&tpmif->tpmif_list, &tpmif_list);
 	num_frontends++;
 
 	return tpmif;
+
+ out_of_memory:
+	if (tpmif != NULL) {
+		kfree(tpmif->mmap_pages);
+		kmem_cache_free(tpmif_cachep, tpmif);
+	}
+	printk("%s: out of memory\n", __FUNCTION__);
+	return ERR_PTR(-ENOMEM);
 }
 
 static void free_tpmif(tpmif_t * tpmif)
 {
+	int i;
+
 	num_frontends--;
+
 	list_del(&tpmif->tpmif_list);
-	balloon_dealloc_empty_page_range(tpmif->pagerange, TPMIF_TX_RING_SIZE);
+
+	for (i = 0; i < TPMIF_TX_RING_SIZE; i++)
+		balloon_free_empty_page(tpmif->mmap_pages[i]);
+	kfree(tpmif->mmap_pages);
+
 	kmem_cache_free(tpmif_cachep, tpmif);
 }
 

linux-2.6-xen-sparse/drivers/xen/tpmback/tpmback.c

@@ -253,7 +253,7 @@ int _packet_write(struct packet *pak,
 			return 0;
 		}
 
-		gnttab_set_map_op(&map_op, MMAP_VADDR(tpmif, i),
+		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
 		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
@@ -270,7 +270,7 @@ int _packet_write(struct packet *pak,
 
 		tocopy = min_t(size_t, size - offset, PAGE_SIZE);
 
-		if (copy_from_buffer((void *)(MMAP_VADDR(tpmif, i) |
+		if (copy_from_buffer((void *)(idx_to_kaddr(tpmif, i) |
 					      (tx->addr & ~PAGE_MASK)),
 				     &data[offset], tocopy, isuserbuffer)) {
 			tpmif_put(tpmif);
@@ -278,7 +278,7 @@ int _packet_write(struct packet *pak,
 		}
 		tx->size = tocopy;
 
-		gnttab_set_unmap_op(&unmap_op, MMAP_VADDR(tpmif, i),
+		gnttab_set_unmap_op(&unmap_op, idx_to_kaddr(tpmif, i),
 				    GNTMAP_host_map, handle);
 
 		if (unlikely
@@ -391,7 +391,7 @@ static int packet_read_shmem(struct packet *pak,
 
 		tx = &tpmif->tx->ring[i].req;
 
-		gnttab_set_map_op(&map_op, MMAP_VADDR(tpmif, i),
+		gnttab_set_map_op(&map_op, idx_to_kaddr(tpmif, i),
 				  GNTMAP_host_map, tx->ref, tpmif->domid);
 
 		if (unlikely(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
@@ -414,10 +414,10 @@ static int packet_read_shmem(struct packet *pak,
 		}
 
 		DPRINTK("Copying from mapped memory at %08lx\n",
-			(unsigned long)(MMAP_VADDR(tpmif, i) |
+			(unsigned long)(idx_to_kaddr(tpmif, i) |
 					(tx->addr & ~PAGE_MASK)));
 
-		src = (void *)(MMAP_VADDR(tpmif, i) |
+		src = (void *)(idx_to_kaddr(tpmif, i) |
 			       ((tx->addr & ~PAGE_MASK) + pg_offset));
 		if (copy_to_buffer(&buffer[offset],
 				   src, to_copy, isuserbuffer)) {
@@ -428,7 +428,7 @@ static int packet_read_shmem(struct packet *pak,
 			tpmif->domid, buffer[offset], buffer[offset + 1],
 			buffer[offset + 2], buffer[offset + 3]);
 
-		gnttab_set_unmap_op(&unmap_op, MMAP_VADDR(tpmif, i),
+		gnttab_set_unmap_op(&unmap_op, idx_to_kaddr(tpmif, i),
 				    GNTMAP_host_map, handle);
 
 		if (unlikely