On 2021/1/28 下午10:41, Stefano Garzarella wrote:
The previous implementation wrote only the status of each request.
This patch implements a more accurate block device simulator,
providing a ramdisk-like behavior.
Signed-off-by: Stefano Garzarella
---
v2:
- used %zd %zx to print size_t and ssize_t variables in dev_err()
- removed unnecessary new line [Jason]
- moved VIRTIO_BLK_T_GET_ID in another patch [Jason]
- used push/pull instead of write/read terminology
- added vdpasim_blk_check_range() to avoid overflows [Stefan]
- use vdpasim*_to_cpu instead of le*_to_cpu
- used vringh_kiov_length() helper [Jason]
Acked-by: Jason Wang
---
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 164 ---
1 file changed, 146 insertions(+), 18 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index 999f9ca0b628..fc47e8320358 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -3,6 +3,7 @@
* VDPA simulator for block device.
*
* Copyright (c) 2020, Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2021, Red Hat Inc. All rights reserved.
*
*/
@@ -13,6 +14,7 @@
#include
#include
#include
+#include
#include
#include "vdpa_sim.h"
@@ -36,10 +38,151 @@
static struct vdpasim *vdpasim_blk_dev;
+static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size)
+{
+ u64 range_sectors = range_size >> SECTOR_SHIFT;
+
+ if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)
+ return false;
+
+ if (start_sector > VDPASIM_BLK_CAPACITY)
+ return false;
+
+ if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector)
+ return false;
+
+ return true;
+}
+
+/* Returns 'true' if the request is handled (with or without an I/O error)
+ * and the status is correctly written in the last byte of the 'in iov',
+ * 'false' otherwise.
+ */
+static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
+ struct vdpasim_virtqueue *vq)
+{
+ size_t pushed = 0, to_pull, to_push;
+ struct virtio_blk_outhdr hdr;
+ ssize_t bytes;
+ loff_t offset;
+ u64 sector;
+ u8 status;
+ u32 type;
+ int ret;
+
+ ret = vringh_getdesc_iotlb(>vring, >out_iov, >in_iov,
+ >head, GFP_ATOMIC);
+ if (ret != 1)
+ return false;
+
+ if (vq->out_iov.used < 1 || vq->in_iov.used < 1) {
+ dev_err(>vdpa.dev, "missing headers - out_iov: %u in_iov
%u\n",
+ vq->out_iov.used, vq->in_iov.used);
+ return false;
+ }
+
+ if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) {
+ dev_err(>vdpa.dev, "request in header too short\n");
+ return false;
+ }
+
+ /* The last byte is the status and we checked if the last iov has
+* enough room for it.
+*/
+ to_push = vringh_kiov_length(>in_iov) - 1;
+
+ to_pull = vringh_kiov_length(>out_iov);
+
+ bytes = vringh_iov_pull_iotlb(>vring, >out_iov, ,
+ sizeof(hdr));
+ if (bytes != sizeof(hdr)) {
+ dev_err(>vdpa.dev, "request out header too short\n");
+ return false;
+ }
+
+ to_pull -= bytes;
+
+ type = vdpasim32_to_cpu(vdpasim, hdr.type);
+ sector = vdpasim64_to_cpu(vdpasim, hdr.sector);
+ offset = sector << SECTOR_SHIFT;
+ status = VIRTIO_BLK_S_OK;
+
+ switch (type) {
+ case VIRTIO_BLK_T_IN:
+ if (!vdpasim_blk_check_range(sector, to_push)) {
+ dev_err(>vdpa.dev,
+ "reading over the capacity - offset: 0x%llx len:
0x%zx\n",
+ offset, to_push);
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ bytes = vringh_iov_push_iotlb(>vring, >in_iov,
+ vdpasim->buffer + offset,
+ to_push);
+ if (bytes < 0) {
+ dev_err(>vdpa.dev,
+ "vringh_iov_push_iotlb() error: %zd offset: 0x%llx
len: 0x%zx\n",
+ bytes, offset, to_push);
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ pushed += bytes;
+ break;
+
+ case VIRTIO_BLK_T_OUT:
+ if (!vdpasim_blk_check_range(sector, to_pull)) {
+ dev_err(>vdpa.dev,
+ "writing over the capacity - offset: 0x%llx len:
0x%zx\n",
+ offset, to_pull);
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ bytes
