diff mbox series

[v5,31/38] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg()

Message ID 20200325161249.55095-32-glider@google.com (mailing list archive)
State New, archived
Headers show
Series Add KernelMemorySanitizer infrastructure | expand

Commit Message

Alexander Potapenko March 25, 2020, 4:12 p.m. UTC 
If vring doesn't use the DMA API, KMSAN is unable to tell whether the
memory is initialized by hardware. Explicitly call kmsan_handle_dma()
from vring_map_one_sg() in this case to prevent false positives.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: linux-mm@kvack.org
---

Change-Id: Icc8678289b7084139320fc503898a67aa9803458
---
 drivers/virtio/virtio_ring.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 58b96baa8d488..8b6dee1dfde58 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -11,6 +11,7 @@ 
 #include <linux/module.h>
 #include <linux/hrtimer.h>
 #include <linux/dma-mapping.h>
+#include <linux/kmsan-checks.h>
 #include <xen/xen.h>
 
 #ifdef DEBUG
@@ -326,8 +327,15 @@  static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq,
 				   struct scatterlist *sg,
 				   enum dma_data_direction direction)
 {
-	if (!vq->use_dma_api)
+	if (!vq->use_dma_api) {
+		/*
+		 * If DMA is not used, KMSAN doesn't know that the scatterlist
+		 * is initialized by the hardware. Explicitly check/unpoison it
+		 * depending on the direction.
+		 */
+		kmsan_handle_dma(sg_virt(sg), sg->length, direction);
 		return (dma_addr_t)sg_phys(sg);
+	}
 
 	/*
 	 * We can't use dma_map_sg, because we don't use scatterlists in