Commit b9cdc88d authored by Will Deacon's avatar Will Deacon Committed by Rusty Russell

virtio: 9p: correctly pass physical address to userspace for high pages

When using a virtio transport, the 9p net device may pass the physical
address of a kernel buffer to userspace via a scatterlist inside a
virtqueue. If the kernel buffer is mapped outside of the linear mapping
(e.g. highmem), then virt_to_page will return a bogus value and we will
populate the scatterlist with junk.

This patch uses kmap_to_page when populating the page array for a kernel
buffer.

Cc: stable@kernel.org
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent f0263d2d
......@@ -39,6 +39,7 @@
#include <linux/inet.h>
#include <linux/idr.h>
#include <linux/file.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
......@@ -325,7 +326,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
int count = nr_pages;
while (nr_pages) {
s = rest_of_page(data);
pages[index++] = virt_to_page(data);
pages[index++] = kmap_to_page(data);
data += s;
nr_pages--;
}
......
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