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transport-mmio: Rename QueueNum register
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These are further named differently between pci and mmio transport.
PCI transport indicates queue size as queue_size.

To bring consistency between pci and mmio transport,
rename the QueueNumMax and QueueNum
registers to QueueSizeMax and QueueSize respectively.

Fixes: oasis-tcs#163
Reviewed-by: Cornelia Huck <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Reviewed-by: Halil Pasic <[email protected]>
Signed-off-by: Parav Pandit <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
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paravmellanox authored and mstsirkin committed May 19, 2023
1 parent fbb119d commit a7a21e4
Showing 1 changed file with 28 additions and 14 deletions.
42 changes: 28 additions & 14 deletions transport-mmio.tex
Original file line number Diff line number Diff line change
Expand Up @@ -110,24 +110,31 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi
\hline
\mmioreg{QueueSel}{Virtual queue index}{0x030}{W}{%
Writing to this register selects the virtual queue that the
following operations on \field{QueueNumMax}, \field{QueueNum}, \field{QueueReady},
following operations on \field{QueueSizeMax},
\field{QueueSize}, \field{QueueReady},
\field{QueueDescLow}, \field{QueueDescHigh}, \field{QueueDriverlLow}, \field{QueueDriverHigh},
\field{QueueDeviceLow}, \field{QueueDeviceHigh} and \field{QueueReset} apply to. The index
number of the first queue is zero (0x0).
}
\hline
\mmioreg{QueueNumMax}{Maximum virtual queue size}{0x034}{R}{%
\mmioreg{QueueSizeMax}{Maximum virtual queue size}{0x034}{R}{%
Reading from the register returns the maximum size (number of
elements) of the queue the device is ready to process or
zero (0x0) if the queue is not available. This applies to the
queue selected by writing to \field{QueueSel}.
\begin{note}
\field{QueueSizeMax} was previously known as \field{QueueNumMax}.
\end{note}
}
\hline
\mmioreg{QueueNum}{Virtual queue size}{0x038}{W}{%
\mmioreg{QueueSize}{Virtual queue size}{0x038}{W}{%
Queue size is the number of elements in the queue.
Writing to this register notifies the device what size of the
queue the driver will use. This applies to the queue selected by
writing to \field{QueueSel}.
\begin{note}
\field{QueueSize} was previously known as \field{QueueNum}.
\end{note}
}
\hline
\mmioreg{QueueReady}{Virtual queue ready bit}{0x044}{RW}{%
Expand Down Expand Up @@ -308,11 +315,11 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi

Before writing to the \field{DriverFeatures} register, the driver MUST write a value to the \field{DriverFeaturesSel} register.

The driver MUST write a value to \field{QueueNum} which is less than
or equal to the value presented by the device in \field{QueueNumMax}.
The driver MUST write a value to \field{QueueSize} which is less than
or equal to the value presented by the device in \field{QueueSizeMax}.

When \field{QueueReady} is not zero, the driver MUST NOT access
\field{QueueNum}, \field{QueueDescLow}, \field{QueueDescHigh},
\field{QueueSize}, \field{QueueDescLow}, \field{QueueDescHigh},
\field{QueueDriverLow}, \field{QueueDriverHigh}, \field{QueueDeviceLow}, \field{QueueDeviceHigh}.

To stop using the queue the driver MUST write zero (0x0) to this
Expand Down Expand Up @@ -363,14 +370,14 @@ \subsubsection{Virtqueue Configuration}\label{sec:Virtio Transport Options / Vir
and expect a returned value of zero (0x0).

\item Read maximum queue size (number of elements) from
\field{QueueNumMax}. If the returned value is zero (0x0) the
\field{QueueSizeMax}. If the returned value is zero (0x0) the
queue is not available.

\item Allocate and zero the queue memory, making sure the memory
is physically contiguous.

\item Notify the device about the queue size by writing the size to
\field{QueueNum}.
\field{QueueSize}.

\item Write physical addresses of the queue's Descriptor Area,
Driver Area and Device Area to (respectively) the
Expand Down Expand Up @@ -465,25 +472,32 @@ \subsection{Legacy interface}\label{sec:Virtio Transport Options / Virtio Over M
\hline
\mmioreg{QueueSel}{Virtual queue index}{0x030}{W}{%
Writing to this register selects the virtual queue that the
following operations on the \field{QueueNumMax}, \field{QueueNum}, \field{QueueAlign}
following operations on the \field{QueueSizeMax},
\field{QueueSize}, \field{QueueAlign}
and \field{QueuePFN} registers apply to. The index
number of the first queue is zero (0x0).
.
}
\hline
\mmioreg{QueueNumMax}{Maximum virtual queue size}{0x034}{R}{%
\mmioreg{QueueSizeMax}{Maximum virtual queue size}{0x034}{R}{%
Reading from the register returns the maximum size of the queue
the device is ready to process or zero (0x0) if the queue is not
available. This applies to the queue selected by writing to
\field{QueueSel} and is allowed only when \field{QueuePFN} is set to zero
(0x0), so when the queue is not actively used.
\begin{note}
\field{QueueSizeMax} was previously known as \field{QueueNumMax}.
\end{note}
}
\hline
\mmioreg{QueueNum}{Virtual queue size}{0x038}{W}{%
\mmioreg{QueueSize}{Virtual queue size}{0x038}{W}{%
Queue size is the number of elements in the queue.
Writing to this register notifies the device what size of the
queue the driver will use. This applies to the queue selected by
writing to \field{QueueSel}.
\begin{note}
\field{QueueSize} was previously known as \field{QueueNum}.
\end{note}
}
\hline
\mmioreg{QueueAlign}{Used Ring alignment in the virtual queue}{0x03c}{W}{%
Expand Down Expand Up @@ -543,16 +557,16 @@ \subsection{Legacy interface}\label{sec:Virtio Transport Options / Virtio Over M
expecting a returned value of zero (0x0).

\item Read maximum queue size (number of elements) from
\field{QueueNumMax}. If the returned value is zero (0x0) the
\field{QueueSizeMax}. If the returned value is zero (0x0) the
queue is not available.

\item Allocate and zero the queue pages in contiguous virtual
memory, aligning the Used Ring to an optimal boundary (usually
page size). The driver should choose a queue size smaller than or
equal to \field{QueueNumMax}.
equal to \field{QueueSizeMax}.

\item Notify the device about the queue size by writing the size to
\field{QueueNum}.
\field{QueueSize}.

\item Notify the device about the used alignment by writing its value
in bytes to \field{QueueAlign}.
Expand Down

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