On 6/7/25 02:10, John Levon wrote:
> For vfio-user, the region write implementation needs to know if the
> write is posted; add the necessary plumbing to support this.
>
> Signed-off-by: John Levon <john.levon@nutanix.com>
> Reviewed-by: Cédric Le Goater <clg@redhat.com>
Applied to vfio-next.
Thanks,
C.
> ---
> include/hw/vfio/vfio-device.h | 4 ++--
> include/hw/vfio/vfio-region.h | 1 +
> hw/vfio/device.c | 3 ++-
> hw/vfio/pci.c | 5 ++++-
> hw/vfio/region.c | 3 ++-
> 5 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
> index 5cb817fd6a..a23ef4ea13 100644
> --- a/include/hw/vfio/vfio-device.h
> +++ b/include/hw/vfio/vfio-device.h
> @@ -207,10 +207,10 @@ struct VFIODeviceIOOps {
> * @region_write
> *
> * Write @size bytes to the region @nr at offset @off from the buffer
> - * @data.
> + * @data; if @post, the write is posted.
> */
> int (*region_write)(VFIODevice *vdev, uint8_t nr, off_t off, uint32_t size,
> - void *data);
> + void *data, bool post);
> };
>
> void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
> diff --git a/include/hw/vfio/vfio-region.h b/include/hw/vfio/vfio-region.h
> index cbffb26962..ede6e0c8f9 100644
> --- a/include/hw/vfio/vfio-region.h
> +++ b/include/hw/vfio/vfio-region.h
> @@ -29,6 +29,7 @@ typedef struct VFIORegion {
> uint32_t nr_mmaps;
> VFIOMmap *mmaps;
> uint8_t nr; /* cache the region number for debug */
> + bool post_wr; /* writes can be posted */
> } VFIORegion;
>
>
> diff --git a/hw/vfio/device.c b/hw/vfio/device.c
> index 29a8d72deb..ad0bac9765 100644
> --- a/hw/vfio/device.c
> +++ b/hw/vfio/device.c
> @@ -569,7 +569,8 @@ static int vfio_device_io_region_read(VFIODevice *vbasedev, uint8_t index,
> }
>
> static int vfio_device_io_region_write(VFIODevice *vbasedev, uint8_t index,
> - off_t off, uint32_t size, void *data)
> + off_t off, uint32_t size, void *data,
> + bool post)
> {
> struct vfio_region_info *info;
> int ret;
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 714d37e227..d68c1412d2 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1015,7 +1015,7 @@ static int vfio_pci_config_space_write(VFIOPCIDevice *vdev, off_t offset,
> {
> return vdev->vbasedev.io_ops->region_write(&vdev->vbasedev,
> VFIO_PCI_CONFIG_REGION_INDEX,
> - offset, size, data);
> + offset, size, data, false);
> }
>
> static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size)
> @@ -1819,6 +1819,9 @@ static void vfio_bar_prepare(VFIOPCIDevice *vdev, int nr)
> bar->type = pci_bar & (bar->ioport ? ~PCI_BASE_ADDRESS_IO_MASK :
> ~PCI_BASE_ADDRESS_MEM_MASK);
> bar->size = bar->region.size;
> +
> + /* IO regions are sync, memory can be async */
> + bar->region.post_wr = (bar->ioport == 0);
> }
>
> static void vfio_bars_prepare(VFIOPCIDevice *vdev)
> diff --git a/hw/vfio/region.c b/hw/vfio/region.c
> index cb172f2136..f5b8e3cbf1 100644
> --- a/hw/vfio/region.c
> +++ b/hw/vfio/region.c
> @@ -66,7 +66,7 @@ void vfio_region_write(void *opaque, hwaddr addr,
> }
>
> ret = vbasedev->io_ops->region_write(vbasedev, region->nr,
> - addr, size, &buf);
> + addr, size, &buf, region->post_wr);
> if (ret != size) {
> error_report("%s(%s:region%d+0x%"HWADDR_PRIx", 0x%"PRIx64
> ",%d) failed: %s",
> @@ -200,6 +200,7 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
> region->size = info->size;
> region->fd_offset = info->offset;
> region->nr = index;
> + region->post_wr = false;
>
> if (region->size) {
> region->mem = g_new0(MemoryRegion, 1);