diff options
| author | mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652> | 2014-03-02 21:35:34 +0000 |
|---|---|---|
| committer | mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652> | 2014-03-02 21:35:34 +0000 |
| commit | 6c55d867ebbac11da6e16323fd4b7b2e386f329f (patch) | |
| tree | cca38182d4b1858c2d6b6ce5a889dcc8d5b4c6fb | |
| parent | ea07d76b67881e6126b4bb3bf10541f83deeea5e (diff) | |
legacy feature bits: confirmance statements
Change accepted on VIRTIO TC Meeting, 3 December 2013
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
git-svn-id: https://tools.oasis-open.org/version-control/svn/virtio@296 0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652
| -rw-r--r-- | content.tex | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/content.tex b/content.tex index 20a61d6..d6cafc6 100644 --- a/content.tex +++ b/content.tex @@ -4787,23 +4787,27 @@ if VIRTIO_F_VERSION_1 is not accepted. \section{Legacy Interface: Reserved Feature Bits}\label{sec:Reserved Feature Bits / Legacy Interface: Reserved Feature Bits} -Legacy or transitional devices may offer the following: - +Transitional devices MAY offer the following: \begin{description} -\item[VIRTIO_F_NOTIFY_ON_EMPTY (24)] Negotiating this feature - indicates that the driver wants an interrupt if the device runs +\item[VIRTIO_F_NOTIFY_ON_EMPTY (24)] If this feature + has been negotiated by driver, the device MUST issue + an interrupt if the device runs out of available descriptors on a virtqueue, even though interrupts are suppressed using the VRING_AVAIL_F_NO_INTERRUPT flag or the \field{used_event} field. \begin{note} - An example of this is the + An example of a driver using this feature is the legacy networking driver: it doesn't need to know every time a packet is transmitted, but it does need to free the transmitted packets a finite time after they are transmitted. It can avoid using a timer if the device interrupts it when all the packets are transmitted. \end{note} +\end{description} +Transitional devices MUST offer, and if offered by the device +traditional drivers MUST negotiate the following: +\begin{description} \item[VIRTIO_F_ANY_LAYOUT (27)] This feature indicates that the device accepts arbitrary descriptor layouts, as described in Section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing}~\nameref{sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing}. |