On Tue, Nov 17, 2020 at 11:36:36AM +0000, Stefan Hajnoczi wrote:

On Fri, Nov 13, 2020 at 02:47:12PM +0100, Stefano Garzarella wrote:

quoted

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 8e41b3ab98d5..68e74383322f 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c

@@ -7,6 +7,7 @@
  */

 #include <linux/module.h>
+#include <linux/blkdev.h>
 #include <uapi/linux/virtio_blk.h>

 #include "vdpa_sim.h"

@@ -24,10 +25,137 @@

 static struct vdpasim *vdpasim_blk_dev;

+static int vdpasim_blk_handle_req(struct vdpasim *vdpasim,
+				  struct vdpasim_virtqueue *vq)

This function has a non-standard int return value. Please document it.

Yes, I'll do.

quoted

+{
+	size_t wrote = 0, to_read = 0, to_write = 0;
+	struct virtio_blk_outhdr hdr;
+	uint8_t status;
+	uint32_t type;
+	ssize_t bytes;
+	loff_t offset;
+	int i, ret;
+
+	vringh_kiov_cleanup(&vq->riov);
+	vringh_kiov_cleanup(&vq->wiov);
+
+	ret = vringh_getdesc_iotlb(&vq->vring, &vq->riov, &vq->wiov,
+				   &vq->head, GFP_ATOMIC);
+	if (ret != 1)
+		return ret;
+
+	for (i = 0; i < vq->wiov.used; i++)
+		to_write += vq->wiov.iov[i].iov_len;
+	to_write -= 1; /* last byte is the status */

What if vq->wiov.used == 0?

Right, we should discard the descriptor.

quoted

+
+	for (i = 0; i < vq->riov.used; i++)
+		to_read += vq->riov.iov[i].iov_len;
+
+	bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->riov, &hdr, sizeof(hdr));
+	if (bytes != sizeof(hdr))
+		return 0;
+
+	to_read -= bytes;
+
+	type = le32_to_cpu(hdr.type);
+	offset = le64_to_cpu(hdr.sector) << SECTOR_SHIFT;
+	status = VIRTIO_BLK_S_OK;
+
+	switch (type) {
+	case VIRTIO_BLK_T_IN:
+		if (offset + to_write > VDPASIM_BLK_CAPACITY << SECTOR_SHIFT) {

Integer overflow is not handled.

I'll fix.

Thanks,
Stefano

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