From 619a2785480f3275767b81a02cead33aaba4e801 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 9 Mar 2018 23:23:34 +0200 Subject: split-ring: generalize text Update generic text to talk about available/used buffers, not rings. Move some split-ring specific text to the correct section. Update conformance section with link to the new conformance clause. Signed-off-by: Michael S. Tsirkin Approved-by: https://www.oasis-open.org/apps/org/workgroup/virtio/ballot.php?id=3177 Fixes: https://github.com/oasis-tcs/virtio-spec/issues/3 --- conformance.tex | 1 + content.tex | 10 ++++------ split-ring.tex | 4 ++++ 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/conformance.tex b/conformance.tex index 55d17b4..e4efe33 100644 --- a/conformance.tex +++ b/conformance.tex @@ -38,6 +38,7 @@ A driver MUST conform to the following normative statements: \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table} \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors} \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Interrupt Suppression} +\item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Available Ring} \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring} \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Notification Suppression} \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / Supplying Buffers to The Device / Updating idx} diff --git a/content.tex b/content.tex index 60f51bb..c577133 100644 --- a/content.tex +++ b/content.tex @@ -381,12 +381,10 @@ of a device are live once the device has been reset. \drivernormative{\subsection}{Device Cleanup}{General Initialization And Device Operation / Device Cleanup} -A driver MUST NOT alter descriptor table entries which have been -exposed in the available ring (and not marked consumed by the device -in the used ring) of a live virtqueue. - -A driver MUST NOT decrement the available \field{idx} on a live virtqueue (ie. -there is no way to ``unexpose'' buffers). +A driver MUST NOT alter virtqueue entries for exposed buffers - +i.e. buffers which have been +made available to the device (and not been used by the device) +of a live virtqueue. Thus a driver MUST ensure a virtqueue isn't live (by device reset) before removing exposed buffers. diff --git a/split-ring.tex b/split-ring.tex index 9601a53..a594d41 100644 --- a/split-ring.tex +++ b/split-ring.tex @@ -296,6 +296,10 @@ referred to this structure as vring_avail, and the constant as VRING_AVAIL_F_NO_INTERRUPT, but the layout and value were identical. \end{note} +\drivernormative{\subsubsection}{The Virtqueue Available Ring}{Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Available Ring} +A driver MUST NOT decrement the available \field{idx} on a virtqueue (ie. +there is no way to ``unexpose'' buffers). + \subsection{Virtqueue Interrupt Suppression}\label{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Interrupt Suppression} If the VIRTIO_F_EVENT_IDX feature bit is not negotiated, -- cgit v1.2.3