On Tue, Jan 30, 2018 at 11:31:18AM +0100, Cornelia Huck wrote:
> On Tue, 23 Jan 2018 02:01:05 +0200
> "Michael S. Tsirkin" <> wrote:
>
>
> Signed-off-by: Michael S. Tsirkin <>
> > ---
>
> content.tex | 14 ++++++
--------
>
> 1 file changed, 6 insertions(+), 8 deletions(-)
> >
>
> diff --git a/content.tex b/content.tex
>
> index 9fc9673..5634c7d 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -1467,8 +1467,7 @@ All register values are organized as Little Endian.
> >
}
> >
\hline
> >
\mmioreg{QueueNum}{Virtual queue size}{0x038}{W}{%
> > -
Queue size is the number of elements in the queue, therefore in each
> > -
of the Descriptor Table, the Available Ring and the Used Ring.
> > +
Queue size is the number of elements in the queue.
>
>
Writing to this register notifies the device what size of the
>
>
queue the driver will use. This applies to the queue selected by
>
>
writing to \field{QueueSel}.
> > @@ -1491,9 +1490,9 @@ All register values are organized as Little Endian.
>
>
caused the device interrupt to be asserted.
>
>
The following events are possible:
> >
\begin{description}
> > -
\item[Used Ring Update] - bit 0 - the interrupt was asserted
> > -
because the device has updated the Used
> > -
Ring in at least one of the active virtual queues.
> > +
\item[Used Buffer Update] - bit 0 - the interrupt was asserted
> > +
because the device has used a buffer
> > +
in at least one of the active virtual queues.
> >
\item [Configuration Change] - bit 1 - the interrupt was
>
>
asserted because the configuration of the device has changed.
> >
\end{description}
> > @@ -1642,9 +1641,8 @@ The driver will typically initialize the virtual queue in the following way:
> >
\field{QueueNumMax}. If the returned value is zero (0x0) the
>
>
queue is not available.
> >
> > -\item Allocate and zero the queue pages, making sure the memory
> > -
is physically contiguous. It is recommended to align the
> > -
Used Ring to an optimal boundary (usually the page size).
> > +\item Allocate and zero the queue memory, making sure the memory
> > +
is physically contiguous.
>
> What about recommendations of that type? Will we want some kind of
> "best practice" suggestions (layout and/or transport specific?)
I don't really know what was this in aid of. When is page size an
optimal boundary? I suspect it never is. I suspect cache line alignment
is a good idea generally but I'm not sure. Want to write something up?
It's also unlikely to be transport specific.
> >
> > \item Notify the device about the queue size by writing the size to
> >
\field{QueueNum}.
>
> Reviewed-by: Cornelia Huck <>
