Fix address calculation for message-based DMA (#740)
The correct DMA address is formed by adding base and offset - the latter
was accidentally missing. Change the server example to read and write
blocks at non-zero offsets, such that `test-client-server.sh` exercises
offset handling.
Signed-off-by: Mattias Nissler <mnissler@rivosinc.com>
diff --git a/lib/libvfio-user.c b/lib/libvfio-user.c
index 94524a2..663d2cd 100644
--- a/lib/libvfio-user.c
+++ b/lib/libvfio-user.c
@@ -2198,7 +2198,7 @@
while (remaining > 0) {
int ret;
- dma_req->addr = (uintptr_t)sg->dma_addr + count;
+ dma_req->addr = (uintptr_t)sg->dma_addr + sg->offset + count;
dma_req->count = MIN(remaining, vfu_ctx->client_max_data_xfer_size);
if (cmd == VFIO_USER_DMA_WRITE) {
diff --git a/samples/server.c b/samples/server.c
index e059d9c..37c5d78 100644
--- a/samples/server.c
+++ b/samples/server.c
@@ -196,42 +196,56 @@
*/
static void do_dma_io(vfu_ctx_t *vfu_ctx, struct server_data *server_data)
{
- int count = 4096;
- unsigned char buf[count];
+ const int size = 1024;
+ const int count = 4;
+ unsigned char buf[size * count];
uint32_t crc1, crc2;
dma_sg_t *sg;
+ void *addr;
int ret;
sg = alloca(dma_sg_size());
assert(vfu_ctx != NULL);
- ret = vfu_addr_to_sgl(vfu_ctx,
- (vfu_dma_addr_t)server_data->regions[0].iova.iov_base,
- count, sg, 1, PROT_WRITE);
- if (ret < 0) {
- err(EXIT_FAILURE, "failed to map %p-%p",
- server_data->regions[0].iova.iov_base,
- server_data->regions[0].iova.iov_base + count -1);
+ /* Write some data, chunked into multiple calls to exercise offsets. */
+ for (int i = 0; i < count; ++i) {
+ addr = server_data->regions[0].iova.iov_base + i * size;
+ ret = vfu_addr_to_sgl(vfu_ctx, (vfu_dma_addr_t)addr, size, sg, 1,
+ PROT_WRITE);
+ if (ret < 0) {
+ err(EXIT_FAILURE, "failed to map %p-%p", addr, addr + size - 1);
+ }
+
+ memset(&buf[i * size], 'A' + i, size);
+ vfu_log(vfu_ctx, LOG_DEBUG, "%s: WRITE addr %p size %d", __func__, addr,
+ size);
+ ret = vfu_sgl_write(vfu_ctx, sg, 1, &buf[i * size]);
+ if (ret < 0) {
+ err(EXIT_FAILURE, "vfu_sgl_write failed");
+ }
}
- memset(buf, 'A', count);
- crc1 = rte_hash_crc(buf, count, 0);
- vfu_log(vfu_ctx, LOG_DEBUG, "%s: WRITE addr %p count %d", __func__,
- server_data->regions[0].iova.iov_base, count);
- ret = vfu_sgl_write(vfu_ctx, sg, 1, buf);
- if (ret < 0) {
- err(EXIT_FAILURE, "vfu_sgl_write failed");
+ crc1 = rte_hash_crc(buf, sizeof(buf), 0);
+
+ /* Read the data back at double the chunk size. */
+ memset(buf, 0, sizeof(buf));
+ for (int i = 0; i < count; i += 2) {
+ addr = server_data->regions[0].iova.iov_base + i * size;
+ ret = vfu_addr_to_sgl(vfu_ctx, (vfu_dma_addr_t)addr, size * 2, sg, 1,
+ PROT_READ);
+ if (ret < 0) {
+ err(EXIT_FAILURE, "failed to map %p-%p", addr, addr + 2 * size - 1);
+ }
+ vfu_log(vfu_ctx, LOG_DEBUG, "%s: READ addr %p size %d", __func__, addr,
+ 2 * size);
+ ret = vfu_sgl_read(vfu_ctx, sg, 1, &buf[i * size]);
+ if (ret < 0) {
+ err(EXIT_FAILURE, "vfu_sgl_read failed");
+ }
}
- memset(buf, 0, count);
- vfu_log(vfu_ctx, LOG_DEBUG, "%s: READ addr %p count %d", __func__,
- server_data->regions[0].iova.iov_base, count);
- ret = vfu_sgl_read(vfu_ctx, sg, 1, buf);
- if (ret < 0) {
- err(EXIT_FAILURE, "vfu_sgl_read failed");
- }
- crc2 = rte_hash_crc(buf, count, 0);
+ crc2 = rte_hash_crc(buf, sizeof(buf), 0);
if (crc1 != crc2) {
errx(EXIT_FAILURE, "DMA write and DMA read mismatch");
