diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index 84a1cea1f43b9a3331b35093e4c57cb78d670815..309648c17f48685c8a115bcb1e03dd0212a35f49 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -63,11 +63,12 @@ static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
unsigned long __pfn_to_mfn(unsigned long pfn)
{
- struct rb_node *n = phys_to_mach.rb_node;
+ struct rb_node *n;
struct xen_p2m_entry *entry;
unsigned long irqflags;
read_lock_irqsave(&p2m_lock, irqflags);
+ n = phys_to_mach.rb_node;
while (n) {
entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
if (entry->pfn <= pfn &&
@@ -152,10 +153,11 @@ bool __set_phys_to_machine_multi(unsigned long pfn,
int rc;
unsigned long irqflags;
struct xen_p2m_entry *p2m_entry;
- struct rb_node *n = phys_to_mach.rb_node;
+ struct rb_node *n;
if (mfn == INVALID_P2M_ENTRY) {
write_lock_irqsave(&p2m_lock, irqflags);
+ n = phys_to_mach.rb_node;
while (n) {
p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
if (p2m_entry->pfn <= pfn &&
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 33f04ef78984c77ed32b576d38729b2d65aa7126..3646c0cae672a338bc92d64c649417b328ebe3b6 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -152,6 +152,10 @@ static unsigned int xen_blkif_max_ring_order;
module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444);
MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
+static bool __read_mostly xen_blkif_trusted = true;
+module_param_named(trusted, xen_blkif_trusted, bool, 0644);
+MODULE_PARM_DESC(trusted, "Is the backend trusted");
+
#define BLK_RING_SIZE(info) \
__CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages)
@@ -210,6 +214,7 @@ struct blkfront_info
unsigned int feature_discard:1;
unsigned int feature_secdiscard:1;
unsigned int feature_persistent:1;
+ unsigned int bounce:1;
unsigned int discard_granularity;
unsigned int discard_alignment;
/* Number of 4KB segments handled */
@@ -310,8 +315,8 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
if (!gnt_list_entry)
goto out_of_memory;
- if (info->feature_persistent) {
- granted_page = alloc_page(GFP_NOIO);
+ if (info->bounce) {
+ granted_page = alloc_page(GFP_NOIO | __GFP_ZERO);
if (!granted_page) {
kfree(gnt_list_entry);
goto out_of_memory;
@@ -330,7 +335,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
list_for_each_entry_safe(gnt_list_entry, n,
&rinfo->grants, node) {
list_del(&gnt_list_entry->node);
- if (info->feature_persistent)
+ if (info->bounce)
__free_page(gnt_list_entry->page);
kfree(gnt_list_entry);
i--;
@@ -376,7 +381,7 @@ static struct grant *get_grant(grant_ref_t *gref_head,
/* Assign a gref to this page */
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
BUG_ON(gnt_list_entry->gref == -ENOSPC);
- if (info->feature_persistent)
+ if (info->bounce)
grant_foreign_access(gnt_list_entry, info);
else {
/* Grant access to the GFN passed by the caller */
@@ -400,7 +405,7 @@ static struct grant *get_indirect_grant(grant_ref_t *gref_head,
/* Assign a gref to this page */
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
BUG_ON(gnt_list_entry->gref == -ENOSPC);
- if (!info->feature_persistent) {
+ if (!info->bounce) {
struct page *indirect_page;
/* Fetch a pre-allocated page to use for indirect grefs */
@@ -703,7 +708,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
.grant_idx = 0,
.segments = NULL,
.rinfo = rinfo,
- .need_copy = rq_data_dir(req) && info->feature_persistent,
+ .need_copy = rq_data_dir(req) && info->bounce,
};
/*
@@ -981,11 +986,12 @@ static void xlvbd_flush(struct blkfront_info *info)
{
blk_queue_write_cache(info->rq, info->feature_flush ? true : false,
info->feature_fua ? true : false);
- pr_info("blkfront: %s: %s %s %s %s %s\n",
+ pr_info("blkfront: %s: %s %s %s %s %s %s %s\n",
info->gd->disk_name, flush_info(info),
"persistent grants:", info->feature_persistent ?
"enabled;" : "disabled;", "indirect descriptors:",
- info->max_indirect_segments ? "enabled;" : "disabled;");
+ info->max_indirect_segments ? "enabled;" : "disabled;",
+ "bounce buffer:", info->bounce ? "enabled" : "disabled;");
}
static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
@@ -1207,7 +1213,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo)
if (!list_empty(&rinfo->indirect_pages)) {
struct page *indirect_page, *n;
- BUG_ON(info->feature_persistent);
+ BUG_ON(info->bounce);
list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
list_del(&indirect_page->lru);
__free_page(indirect_page);
@@ -1224,7 +1230,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo)
NULL);
rinfo->persistent_gnts_c--;
}
- if (info->feature_persistent)
+ if (info->bounce)
__free_page(persistent_gnt->page);
kfree(persistent_gnt);
}
@@ -1245,7 +1251,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo)
for (j = 0; j < segs; j++) {
persistent_gnt = rinfo->shadow[i].grants_used[j];
gnttab_end_foreign_access(persistent_gnt->gref, NULL);
- if (info->feature_persistent)
+ if (info->bounce)
__free_page(persistent_gnt->page);
kfree(persistent_gnt);
}
@@ -1428,7 +1434,7 @@ static int blkif_completion(unsigned long *id,
data.s = s;
num_sg = s->num_sg;
- if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
+ if (bret->operation == BLKIF_OP_READ && info->bounce) {
for_each_sg(s->sg, sg, num_sg, i) {
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
@@ -1487,7 +1493,7 @@ static int blkif_completion(unsigned long *id,
* Add the used indirect page back to the list of
* available pages for indirect grefs.
*/
- if (!info->feature_persistent) {
+ if (!info->bounce) {
indirect_page = s->indirect_grants[i]->page;
list_add(&indirect_page->lru, &rinfo->indirect_pages);
}
@@ -1764,6 +1770,10 @@ static int talk_to_blkback(struct xenbus_device *dev,
if (!info)
return -ENODEV;
+ /* Check if backend is trusted. */
+ info->bounce = !xen_blkif_trusted ||
+ !xenbus_read_unsigned(dev->nodename, "trusted", 1);
+
max_page_order = xenbus_read_unsigned(info->xbdev->otherend,
"max-ring-page-order", 0);
ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
@@ -2173,17 +2183,18 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
if (err)
goto out_of_memory;
- if (!info->feature_persistent && info->max_indirect_segments) {
+ if (!info->bounce && info->max_indirect_segments) {
/*
- * We are using indirect descriptors but not persistent
- * grants, we need to allocate a set of pages that can be
+ * We are using indirect descriptors but don't have a bounce
+ * buffer, we need to allocate a set of pages that can be
* used for mapping indirect grefs
*/
int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info);
BUG_ON(!list_empty(&rinfo->indirect_pages));
for (i = 0; i < num; i++) {
- struct page *indirect_page = alloc_page(GFP_KERNEL);
+ struct page *indirect_page = alloc_page(GFP_KERNEL |
+ __GFP_ZERO);
if (!indirect_page)
goto out_of_memory;
list_add(&indirect_page->lru, &rinfo->indirect_pages);
@@ -2276,6 +2287,8 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
info->feature_persistent =
!!xenbus_read_unsigned(info->xbdev->otherend,
"feature-persistent", 0);
+ if (info->feature_persistent)
+ info->bounce = true;
indirect_segments = xenbus_read_unsigned(info->xbdev->otherend,
"feature-max-indirect-segments", 0);
@@ -2547,6 +2560,13 @@ static void blkfront_delay_work(struct work_struct *work)
struct blkfront_info *info;
bool need_schedule_work = false;
+ /*
+ * Note that when using bounce buffers but not persistent grants
+ * there's no need to run blkfront_delay_work because grants are
+ * revoked in blkif_completion or else an error is reported and the
+ * connection is closed.
+ */
+
mutex_lock(&blkfront_mutex);
list_for_each_entry(info, &info_list, info_list) {
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 8c0b9546d5a2d6e7620ffcf9f1f9385f08842187..2409007f1fd96e9fccdcb16ee8333d615f45b409 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -66,6 +66,10 @@ module_param_named(max_queues, xennet_max_queues, uint, 0644);
MODULE_PARM_DESC(max_queues,
"Maximum number of queues per virtual interface");
+static bool __read_mostly xennet_trusted = true;
+module_param_named(trusted, xennet_trusted, bool, 0644);
+MODULE_PARM_DESC(trusted, "Is the backend trusted");
+
#define XENNET_TIMEOUT (5 * HZ)
static const struct ethtool_ops xennet_ethtool_ops;
@@ -173,6 +177,9 @@ struct netfront_info {
/* Is device behaving sane? */
bool broken;
+ /* Should skbs be bounced into a zeroed buffer? */
+ bool bounce;
+
atomic_t rx_gso_checksum_fixup;
};
@@ -271,7 +278,8 @@ static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
if (unlikely(!skb))
return NULL;
- page = page_pool_dev_alloc_pages(queue->page_pool);
+ page = page_pool_alloc_pages(queue->page_pool,
+ GFP_ATOMIC | __GFP_NOWARN | __GFP_ZERO);
if (unlikely(!page)) {
kfree_skb(skb);
return NULL;
@@ -665,6 +673,33 @@ static int xennet_xdp_xmit(struct net_device *dev, int n,
return nxmit;
}
+struct sk_buff *bounce_skb(const struct sk_buff *skb)
+{
+ unsigned int headerlen = skb_headroom(skb);
+ /* Align size to allocate full pages and avoid contiguous data leaks */
+ unsigned int size = ALIGN(skb_end_offset(skb) + skb->data_len,
+ XEN_PAGE_SIZE);
+ struct sk_buff *n = alloc_skb(size, GFP_ATOMIC | __GFP_ZERO);
+
+ if (!n)
+ return NULL;
+
+ if (!IS_ALIGNED((uintptr_t)n->head, XEN_PAGE_SIZE)) {
+ WARN_ONCE(1, "misaligned skb allocated\n");
+ kfree_skb(n);
+ return NULL;
+ }
+
+ /* Set the data pointer */
+ skb_reserve(n, headerlen);
+ /* Set the tail pointer and length */
+ skb_put(n, skb->len);
+
+ BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
+
+ skb_copy_header(n, skb);
+ return n;
+}
#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
@@ -718,9 +753,13 @@ static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev
/* The first req should be at least ETH_HLEN size or the packet will be
* dropped by netback.
+ *
+ * If the backend is not trusted bounce all data to zeroed pages to
+ * avoid exposing contiguous data on the granted page not belonging to
+ * the skb.
*/
- if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
- nskb = skb_copy(skb, GFP_ATOMIC);
+ if (np->bounce || unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
+ nskb = bounce_skb(skb);
if (!nskb)
goto drop;
dev_consume_skb_any(skb);
@@ -1053,8 +1092,10 @@ static int xennet_get_responses(struct netfront_queue *queue,
}
}
rcu_read_unlock();
-next:
+
__skb_queue_tail(list, skb);
+
+next:
if (!(rx->flags & XEN_NETRXF_more_data))
break;
@@ -2214,6 +2255,10 @@ static int talk_to_netback(struct xenbus_device *dev,
info->netdev->irq = 0;
+ /* Check if backend is trusted. */
+ info->bounce = !xennet_trusted ||
+ !xenbus_read_unsigned(dev->nodename, "trusted", 1);
+
/* Check if backend supports multiple queues */
max_queues = xenbus_read_unsigned(info->xbdev->otherend,
"multi-queue-max-queues", 1);
@@ -2381,6 +2426,9 @@ static int xennet_connect(struct net_device *dev)
return err;
if (np->netback_has_xdp_headroom)
pr_info("backend supports XDP headroom\n");
+ if (np->bounce)
+ dev_info(&np->xbdev->dev,
+ "bouncing transmitted data to zeroed pages\n");
/* talk_to_netback() sets the correct number of queues */
num_queues = dev->real_num_tx_queues;