On Wed, 10 Jan 2018 11:47:55 +0200 "Michael S. Tsirkin" <> wrote:
> Signed-off-by: Michael S. Tsirkin <> > ---
> content.tex
25 ++++++++++++++++++++++++-
> 1 file changed, 24 insertions(+), 1 deletion(-) >
> diff --git a/content.tex b/content.tex
> index c7ef7fd..4483a4b 100644 > --- a/content.tex > +++ b/content.tex > @@ -230,7 +230,30 @@ result.
> The mechanism for bulk data transport on virtio devices is
> pretentiously called a virtqueue. Each device can have zero or more
> virtqueuesfootnote{For example, the simplest network device has one virtqueue for > -transmit and one for receive.}. Each queue has a 16-bit queue size > +transmit and one for receive.}. > + > +Driver makes requests available to device by adding > +an available buffer to the queue - i.e. adding a buffer > +describing the request to a virtqueue, and optionally triggering > +a driver event - i.e. sending a notification to the device. > + > +Device executes the requests and - when complete - adds > +a used buffer to the queue - i.e. lets the driver > +know by marking the buffer as used. Device can then trigger > +a device event - i.e. send an interrupt to the driver. > + > +For queue operation detail, see
ef{sec:Basic Facilities of a Virtio Device / Split Virtqueues}~
ameref{sec:Basic Facilities of a Virtio Device / Split Virtqueues}. > + > +section{Split Virtqueues}label{sec:Basic Facilities of a Virtio Device / Split Virtqueues} > +The split virtqueue format is the original format used by legacy > +virtio devices.
I think the term 'legacy' is a bit confusing here. Elsewhere, 'legacy' refers to pre-standard devices, and while they use a variant of this layout, I don't think we should mix this up with 1.0 devices. What about: "The split virtqueue format is the original format used by devices conforming to the 1.0 version of this standard (and a variant thereof by legacy virtio devices)."
> The split virtqueue format separates the > +virtqueue into several parts, where each part is write-able by > +either the driver or the device, but not both. Multiple > +locations need to be updated when making a buffer available > +and when marking it as used. > + > + > +Each queue has a 16-bit queue size
> parameter, which sets the number of entries and implies the total size
> of the queue. >
