@samitouri / QOSamiQemu / commits / e64eb57443

vfio-user: correct protocol for DMA reads/writes

The "count" parameter in the DMA write reply should be 8 bytes in size. Reported-by: Patrick Mooney <patrick@matx.com> Signed-off-by: John Levon <john.levon@nutanix.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/qemu-devel/20260410085716.877185-3-john.levon@nutanix.com Signed-off-by: Cédric Le Goater <clg@redhat.com>

John Levon committed Apr 10, 2026 at 09:57 UTC e64eb5744325db8f0d4deeaa939c88bcecdac661
2 files changed +2 -2
docs/interop/vfio-user.rst
+1 -1
@@ -1463,7 +1463,7 @@ Reply
1463 +=========+========+==========+
1464 | address | 0 | 8 |
1465 +---------+--------+----------+
1466 -| count | 8 | 4 |
1466 +| count | 8 | 8 |
1467 +---------+--------+----------+
1468
1469 * *address* is the client DMA memory address being accessed.
hw/vfio-user/protocol.h
+1 -1
@@ -210,7 +210,7 @@ typedef struct {
210 typedef struct {
211 VFIOUserHdr hdr;
212 uint64_t offset;
213 - uint32_t count;
213 + uint64_t count;
214 char data[];
215 } VFIOUserDMARW;
216