On Tue, 23 Jan 2018 02:01:09 +0200
"Michael S. Tsirkin" <m...@redhat.com> wrote:
> For a split ring, require that drivers use descriptors in order too.
> This allows devices to skip reading the available ring.
>
> Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> ---
> split-ring.tex | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/split-ring.tex b/split-ring.tex
> index f976e45..43c496c 100644
> --- a/split-ring.tex
> +++ b/split-ring.tex
> @@ -218,6 +222,12 @@ purposes).
> Drivers MUST NOT add a descriptor chain over than $2^{32}$ bytes long in
> total;
> this implies that loops in the descriptor chain are forbidden!
>
> +If VIRTIO_F_IN_ORDER has been negotiated, and when making a
> +descriptor with VRING_DESC_F_NEXT set in \field{flags} at offset
> +$x$ in the table available to the device, driver MUST set
> +\field{next} to $0$ for the last descriptor in the table
> +(where $x = queue_size - 1$) and to $x + 1$ for the rest of the descriptors.
The underscore in queue_size makes this a subscript s, which is
probably not what you want :)
> +
> \subsubsection{Indirect Descriptors}\label{sec:Basic Facilities of a Virtio
> Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors}
>
> Some devices benefit by concurrently dispatching a large number
Otherwise,
Reviewed-by: Cornelia Huck <coh...@redhat.com>
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