Re: [virtio-comment] [PATCH v3 2/4] Add PCI configuration field "queue_indirect_size"

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Mittwoch, 16. März 2022 14:50:22 CET Christian Schoenebeck wrote:
> This new PCI configuration field allows to negotiate a more fine
> graded maximum lenght of indirect descriptor chains.
> 
> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/122
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  content.tex | 26 ++++++++++++++++++++++----
>  1 file changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/content.tex b/content.tex
> index 685525d..5162e2b 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -902,6 +902,7 @@ \subsubsection{Common configuration structure
> layout}\label{sec:Virtio Transport le64 queue_device;              /*
> read-write */
>          le16 queue_notify_data;         /* read-only for driver */
>          le16 queue_reset;               /* read-write */
> +        le32 queue_indirect_size;       /* read-write */
>  };
>  \end{lstlisting}
[...]
> @@ -6870,10 +6888,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
>    to the 16-bit size of a descriptor's "next" field there is still an absolute
>    limit of $2^{16}$ descriptors per indirect descriptor table. However the
>    actual maximum amount supported by either device or driver might be less,
> -  and therefore the bus specific Queue Indirect Size value MUST additionally
> -  be negotiated if VIRTIO_RING_F_INDIRECT_SIZE was negotiated to subsequently
> -  negotiate the actual amount of maximum indirect descriptors supported
> -  by both sides.
> +  and therefore the transport specific Queue Indirect Size value MUST
> +  additionally be negotiated if VIRTIO_RING_F_INDIRECT_SIZE was negotiated to
> +  subsequently negotiate the actual amount of maximum indirect descriptors
> +  supported by both sides.

Oops, I accidentally squashed that change (s/bus/transport/) into this PCI
patch instead of patch 1 as it was supposed to.

I'll wait though if there is still something to address on CCW patch 4 before
posting a v4.

Best regards,
Christian Schoenebeck