Displaying 4 results from an estimated 4 matches for "avail_mapped".
2014 Aug 10
0
[PATCH] vhost: Add polling mode
...vq->avail to the kernel's memory space. */
> + if (get_user_pages_fast((unsigned long)vq->avail, 1, 0,
> + &vq->vqpoll.avail_page) != 1) {
> + /* TODO: can this happen, as we check access
> + to vq->avail in advance? */
> + BUG();
> + }
> + vq->vqpoll.avail_mapped = (struct vring_avail *) (
> + (unsigned long)kmap(vq->vqpoll.avail_page) |
> + ((unsigned long)vq->avail & ~PAGE_MASK));
> +}
> +
> +/*
> + * This function doesn't always succeed in changing the mode. Sometimes
> + * a temporary race condition prevents turning...
2014 Aug 20
0
[PATCH] vhost: Add polling mode
...vq->avail in advance? */
It can since you don't have the mm lock, so userspace can
unmap the page in this window. And especially since you didn't
check __get_user return code, so you don't even know that
it succeeded in the first place.
> + BUG();
> + }
> + vq->vqpoll.avail_mapped = (struct vring_avail *) (
> + (unsigned long)kmap(vq->vqpoll.avail_page) |
> + ((unsigned long)vq->avail & ~PAGE_MASK));
> +}
> +
> +/*
> + * This function doesn't always succeed in changing the mode. Sometimes
> + * a temporary race condition prevents turning...
2014 Aug 10
7
[PATCH] vhost: Add polling mode
...= true;
+
+ /* Map userspace's vq->avail to the kernel's memory space. */
+ if (get_user_pages_fast((unsigned long)vq->avail, 1, 0,
+ &vq->vqpoll.avail_page) != 1) {
+ /* TODO: can this happen, as we check access
+ to vq->avail in advance? */
+ BUG();
+ }
+ vq->vqpoll.avail_mapped = (struct vring_avail *) (
+ (unsigned long)kmap(vq->vqpoll.avail_page) |
+ ((unsigned long)vq->avail & ~PAGE_MASK));
+}
+
+/*
+ * This function doesn't always succeed in changing the mode. Sometimes
+ * a temporary race condition prevents turning on guest notifications, so
+ * vq s...
2014 Aug 10
7
[PATCH] vhost: Add polling mode
...= true;
+
+ /* Map userspace's vq->avail to the kernel's memory space. */
+ if (get_user_pages_fast((unsigned long)vq->avail, 1, 0,
+ &vq->vqpoll.avail_page) != 1) {
+ /* TODO: can this happen, as we check access
+ to vq->avail in advance? */
+ BUG();
+ }
+ vq->vqpoll.avail_mapped = (struct vring_avail *) (
+ (unsigned long)kmap(vq->vqpoll.avail_page) |
+ ((unsigned long)vq->avail & ~PAGE_MASK));
+}
+
+/*
+ * This function doesn't always succeed in changing the mode. Sometimes
+ * a temporary race condition prevents turning on guest notifications, so
+ * vq s...