[v9,5/5] vfio-user: Fix config space access byte order

Commit Message

Mattias Nissler May 7, 2024, 9:42 a.m. UTC

PCI config space is little-endian, so on a big-endian host we need to
perform byte swaps for values as they are passed to and received from
the generic PCI config space access machinery.

Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
Reviewed-by: Stefan Hajnoczi <[e-mail]>
Reviewed-by: Jagannathan Raman <[e-mail]>
Signed-off-by: Mattias Nissler <[e-mail]>
---
 hw/remote/vfio-user-obj.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch

diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c
index a15e291c9a..0e93d7a7b4 100644
--- a/hw/remote/vfio-user-obj.c
+++ b/hw/remote/vfio-user-obj.c
@@ -281,7 +281,7 @@  static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_ctx, char * const buf,
     while (bytes > 0) {
         len = (bytes > pci_access_width) ? pci_access_width : bytes;
         if (is_write) {
-            memcpy(&val, ptr, len);
+            val = ldn_le_p(ptr, len);
             pci_host_config_write_common(o->pci_dev, offset,
                                          pci_config_size(o->pci_dev),
                                          val, len);
@@ -289,7 +289,7 @@  static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_ctx, char * const buf,
         } else {
             val = pci_host_config_read_common(o->pci_dev, offset,
                                               pci_config_size(o->pci_dev), len);
-            memcpy(ptr, &val, len);
+            stn_le_p(ptr, len, val);
             trace_vfu_cfg_read(offset, val);
         }
         offset += len;