On Tue, Dec 14, 2021 at 05:20:33PM +0100, Alexander Potapenko wrote: > 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@xxxxxxxxxx> OK I guess Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> IIUC this depends on the rest of the patchset, so feel free to merge. > --- > Link: https://linux-review.googlesource.com/id/I211533ecb86a66624e151551f83ddd749536b3af > --- > drivers/virtio/virtio_ring.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 6d2614e34470f..bf4d5b331e99d 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 <linux/spinlock.h> > #include <xen/xen.h> > > @@ -331,8 +332,15 @@ 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_page(sg), sg->offset, sg->length, direction); > return (dma_addr_t)sg_phys(sg); > + } > > /* > * We can't use dma_map_sg, because we don't use scatterlists in > -- > 2.34.1.173.g76aa8bc2d0-goog
