Re: [PATCH RFC v2 09/16] vfio-user: region read/write

[John Levon]

On Mon, Aug 16, 2021 at 09:42:42AM -0700, Elena Ufimtseva wrote:

> +int vfio_user_region_write(VFIODevice *vbasedev, uint32_t index,
> +                           uint64_t offset, uint32_t count, void *data)
> +{
> +    g_autofree VFIOUserRegionRW *msgp = NULL;
> +    int size = sizeof(*msgp) + count;
> +
> +    msgp = g_malloc0(size);
> +    vfio_user_request_msg(&msgp->hdr, VFIO_USER_REGION_WRITE, size,
> +                          VFIO_USER_NO_REPLY);

Mirroring https://github.com/oracle/qemu/issues/10 here for visibility:

Currently, vfio_user_region_write uses VFIO_USER_NO_REPLY unconditionally,
meaning essentially all writes are posted. But that shouldn't be the case, for
example for PCI config space, where it's expected that writes will wait for an
ack before the VCPU continues.

regards
john