On Wed, Jan 10, 2018 at 03:15:38PM +0100, Cornelia Huck wrote:
> On Wed, 10 Jan 2018 11:47:58 +0200
> "Michael S. Tsirkin" <[email protected]> wrote:
>
> > Performance analysis of this is in my kvm forum 2016 presentation. The
> > idea is to have a r/w descriptor in a ring structure, replacing the used
> > and available ring, index and descriptor buffer.
>
> Do we have a place to store pointers to such information?
>
> >
> > This is also easier for devices to implement than the 1.0 layout.
> > Several more enhancements will be necessary to actually make this
> > efficient for devices to use.
> >
> > Signed-off-by: Michael S. Tsirkin <[email protected]>
> > ---
> > content.tex | 36 ++-
> > packed-ring.tex | 668
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 701 insertions(+), 3 deletions(-)
> > create mode 100644 packed-ring.tex
> >
> > diff --git a/content.tex b/content.tex
> > index 3b4579e..3059bd3 100644
> > --- a/content.tex
> > +++ b/content.tex
>
> (...)
>
> > @@ -5199,10 +5215,19 @@ Currently these device-independent feature bits
> > defined:
> > \begin{description}
> > \item[VIRTIO_F_RING_INDIRECT_DESC (28)] Negotiating this feature
> > indicates
> > that the driver can use descriptors with the VIRTQ_DESC_F_INDIRECT
> > - flag set, as described in \ref{sec:Basic Facilities of a Virtio Device /
> > Virtqueues / The Virtqueue Descriptor Table / Indirect
> > Descriptors}~\nameref{sec:Basic Facilities of a Virtio Device / Virtqueues
> > / The Virtqueue Descriptor Table / Indirect Descriptors}.
> > + flag set, as described in \ref{sec:Basic Facilities of a Virtio
> > +Device / Virtqueues / The Virtqueue Descriptor Table / Indirect
> > +Descriptors}~\nameref{sec:Basic Facilities of a Virtio Device /
> > +Virtqueues / The Virtqueue Descriptor Table / Indirect
> > +Descriptors} and
> > + \ref{sec:Packed Virtqueues / Indirect Flag: Scatter-Gather Support}
> > +\ref{sec:Packed Virtqueues / Driver and Device Event Suppression}.
>
> That one needs to go below (copy/paste error?).
>
> >
> > \item[VIRTIO_F_RING_EVENT_IDX(29)] This feature enables the
> > \field{used_event}
> > - and the \field{avail_event} fields as described in \ref{sec:Basic
> > Facilities of a Virtio Device / Virtqueues / Virtqueue Interrupt
> > Suppression} and \ref{sec:Basic Facilities of a Virtio Device / Virtqueues
> > / The Virtqueue Used Ring}.
> > + and the \field{avail_event} fields as described in
> > +\ref{sec:Basic Facilities of a Virtio Device / Virtqueues /
> > +Virtqueue Interrupt Suppression}, \ref{sec:Basic Facilities of a Virtio
> > Device / Virtqueues / The Virtqueue Used Ring}
> > +and .
>
> Here's where the ref above needs to go.
>
> >
> > \item[VIRTIO_F_VERSION_1(32)] This indicates compliance with this
> > specification, giving a simple way to detect legacy devices or drivers.
> > @@ -5212,6 +5237,9 @@ Currently these device-independent feature bits
> > defined:
> > addresses in memory. If this feature bit is set to 0, then the device
> > emits
> > physical addresses which are not translated further, even though an IOMMU
> > may be present.
> > + \item[VIRTIO_F_RING_PACKED(34)] This feature indicates
> > + support for the packed virtqueue layout as described in
> > +\ref{sec:Basic Facilities of a Virtio Device / Packed Virtqueues}.
> > \end{description}
>
> I think the references should include a title as well (that makes the
> resulting document easier to read).
Want to add a macro including ref+nameref?
We'd use it for all sec: references then.
> >
> > \drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits}
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