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Subject: [PATCH v4 2/3] virtio: pci support virtqueue reset
PCI support virtqueue reset. virtio_pci_common_cfg add "queue_reset" to support virtqueue reset. The driver uses this to selectively reset the queue. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- content.tex | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/content.tex b/content.tex index 05b05ba..1c35df5 100644 --- a/content.tex +++ b/content.tex @@ -900,6 +900,7 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport le64 queue_driver; /* read-write */ le64 queue_device; /* read-write */ le16 queue_notify_data; /* read-only for driver */ + le16 queue_reset; /* read-write */ }; \end{lstlisting} @@ -979,6 +980,12 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport may benefit from providing another value, for example an internal virtqueue identifier, or an internal offset related to the virtqueue number. \end{note} + +\item[\field{queue_reset}] + The driver uses this to selectively reset the queue. + This field exists only if VIRTIO_F_RING_RESET has been + negotiated. (see \ref{sec:Virtqueues / Virtqueue Reset}). + \end{description} \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout} @@ -1020,6 +1027,20 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport The device MUST present a 0 in \field{queue_enable} on reset. +If VIRTIO_F_RING_RESET has been negotiated, the device MUST present a 0 in +\field{queue_enable} after the driver has reset the virtqueue via +\field{queue_reset}. + +If VIRTIO_F_RING_RESET has been negotiated, the device MUST present a 0 in +\field{queue_reset} on reset. + +If VIRTIO_F_RING_RESET has been negotiated, The device MUST present a 0 in +\field{queue_reset} after the virtqueue is enabled with \field{queue_enable}. + +The device MUST reset the queue when 1 is written to \field{queue_reset}, and +present a 1 in \field{queue_reset} after the queue has been reset, until the +driver re-enables the queue via \field{queue_enable}. (see \ref{sec:Virtqueues / Virtqueue Reset}). + The device MUST present a 0 in \field{queue_size} if the virtqueue corresponding to the current \field{queue_select} is unavailable. @@ -1044,6 +1065,13 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport The driver MUST NOT write a 0 to \field{queue_enable}. +If VIRTIO_F_RING_RESET has been negotiated, after the driver writes 1 to +\field{queue_reset} to reset the queue, it MUST verify that the queue +has been reset by reading back \field{queue_reset} and ensuring that it +is 1. The driver MAY re-enable the queue by writing a 1 to +\field{queue_enable} after ensuring that the other virtqueue fields have +been set up correctly. (see \ref{sec:Virtqueues / Virtqueue Reset}). + \subsubsection{Notification structure layout}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability} The notification location is found using the VIRTIO_PCI_CAP_NOTIFY_CFG -- 2.31.0
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