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-rw-r--r--drivers/xen/balloon.c16
-rw-r--r--drivers/xen/evtchn.c20
2 files changed, 24 insertions, 12 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 9781e0dd59d6..d46839f51e73 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -151,6 +151,8 @@ static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
static void balloon_process(struct work_struct *work);
static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
+static void release_memory_resource(struct resource *resource);
+
/* When ballooning out (allocating memory to return to Xen) we don't really
want the kernel to try too hard since that can trigger the oom killer. */
#define GFP_BALLOON \
@@ -267,6 +269,20 @@ static struct resource *additional_memory_resource(phys_addr_t size)
return NULL;
}
+#ifdef CONFIG_SPARSEMEM
+ {
+ unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT);
+ unsigned long pfn = res->start >> PAGE_SHIFT;
+
+ if (pfn > limit) {
+ pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n",
+ pfn, limit);
+ release_memory_resource(res);
+ return NULL;
+ }
+ }
+#endif
+
return res;
}
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index 38272ad24551..f4edd6df3df2 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -316,7 +316,6 @@ static int evtchn_resize_ring(struct per_user_data *u)
{
unsigned int new_size;
evtchn_port_t *new_ring, *old_ring;
- unsigned int p, c;
/*
* Ensure the ring is large enough to capture all possible
@@ -346,20 +345,17 @@ static int evtchn_resize_ring(struct per_user_data *u)
/*
* Copy the old ring contents to the new ring.
*
- * If the ring contents crosses the end of the current ring,
- * it needs to be copied in two chunks.
+ * To take care of wrapping, a full ring, and the new index
+ * pointing into the second half, simply copy the old contents
+ * twice.
*
* +---------+ +------------------+
- * |34567 12| -> | 1234567 |
- * +-----p-c-+ +------------------+
+ * |34567 12| -> |34567 1234567 12|
+ * +-----p-c-+ +-------c------p---+
*/
- p = evtchn_ring_offset(u, u->ring_prod);
- c = evtchn_ring_offset(u, u->ring_cons);
- if (p < c) {
- memcpy(new_ring + c, u->ring + c, (u->ring_size - c) * sizeof(*u->ring));
- memcpy(new_ring + u->ring_size, u->ring, p * sizeof(*u->ring));
- } else
- memcpy(new_ring + c, u->ring + c, (p - c) * sizeof(*u->ring));
+ memcpy(new_ring, old_ring, u->ring_size * sizeof(*u->ring));
+ memcpy(new_ring + u->ring_size, old_ring,
+ u->ring_size * sizeof(*u->ring));
u->ring = new_ring;
u->ring_size = new_size;