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Subject: [PATCH v7 3/3] virtio: mmio support virtqueue reset
mmio support virtqueue reset. MMIO Device Register Layout "QueueReady" to support virtqueue reset. The driver uses this to selectively reset the queue. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- content.tex | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/content.tex b/content.tex index 219ad2f..c2ed496 100644 --- a/content.tex +++ b/content.tex @@ -1853,7 +1853,7 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi Writing to this register selects the virtual queue that the following operations on \field{QueueNumMax}, \field{QueueNum}, \field{QueueReady}, \field{QueueDescLow}, \field{QueueDescHigh}, \field{QueueDriverlLow}, \field{QueueDriverHigh}, - \field{QueueDeviceLow} and \field{QueueDeviceHigh} apply to. The index + \field{QueueDeviceLow}, \field{QueueDeviceHigh} and \field{QueueReset} apply to. The index number of the first queue is zero (0x0). } \hline @@ -1970,6 +1970,12 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi 0xffffffffffffffff. } \hline + \mmioreg{QueueReset}{Virtual queue reset bit}{0x0c0}{RW}{% + If VIRTIO_F_RING_RESET has been negotiated, writing one (0x1) to this + register selectively resets the queue. Both read and write accesses + apply to the queue selected by writing to \field{QueueSel}. + } + \hline \mmioreg{ConfigGeneration}{Configuration atomicity value}{0x0fc}{R}{ Reading from this register returns a value describing a version of the device-specific configuration space (see \field{Config}). The driver can then access the configuration space and, when finished, read \field{ConfigGeneration} again. @@ -2005,6 +2011,22 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi The device MUST NOT access virtual queue contents when \field{QueueReady} is zero (0x0). +If VIRTIO_F_RING_RESET has been negotiated, the device MUST present a 0 in +\field{QueueReady} after the driver has reset the virtqueue via +\field{QueueReset}. + +If VIRTIO_F_RING_RESET has been negotiated, the device MUST present a 0 in +\field{QueueReset} on reset. + +If VIRTIO_F_RING_RESET has been negotiated, The device MUST present a 0 in +\field{QueueReset} after the virtqueue is enabled with \field{QueueReady}. + +The device MUST reset the queue when 1 is written to \field{QueueReset}, and +present a 1 in \field{QueueReset} after the queue has been reset, until the +driver re-enables the queue via \field{QueueReady} or until the device is reset. +The device MUST present consistent default values after queue reset. +(see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}). + \drivernormative{\subsubsection}{MMIO Device Register Layout}{Virtio Transport Options / Virtio Over MMIO / MMIO Device Register Layout} The driver MUST NOT access memory locations not described in the table \ref{tab:Virtio Trasport Options / Virtio Over MMIO / MMIO Device Register Layout} @@ -2047,6 +2069,15 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi The driver MUST write a value with a bit mask describing events it handled into \field{InterruptACK} when it finishes handling an interrupt and MUST NOT set any of the undefined bits in the value. +If VIRTIO_F_RING_RESET has been negotiated, after the driver writes 1 to +\field{QueueReset} to reset the queue, it MUST verify that the queue +has been reset by reading back \field{QueueReset} and ensuring that it +is 1. The driver MAY re-enable the queue by writing a 1 to +\field{QueueReady} after ensuring that the other virtqueue fields have +been set up correctly. The driver MAY set driver-writeable queue configuration +values to different values than those that were used before the queue reset. +(see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}). + \subsection{MMIO-specific Initialization And Device Operation}\label{sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation} \subsubsection{Device Initialization}\label{sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization} -- 2.31.0
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