diff options
Diffstat (limited to 'content.tex')
| -rw-r--r-- | content.tex | 61 |
1 files changed, 40 insertions, 21 deletions
diff --git a/content.tex b/content.tex index a5aff1c..6be9960 100644 --- a/content.tex +++ b/content.tex @@ -245,6 +245,24 @@ a device event - i.e. send an interrupt to the driver. Device reports the number of bytes it has written to memory for each buffer it uses. This is referred to as ``used length''. +Each virtqueue can consist of up to 3 parts: +\begin{itemize} +\item Descriptor Area - used for describing buffers +\item Driver Area - extra data supplied by driver to the device +\item Device Area - extra data supplied by device to driver +\end{itemize} + +\begin{note} +Note that previous versions of this spec used different names for +these parts (following \ref{sec:Basic Facilities of a Virtio Device / Split Virtqueues}): +\begin{itemize} +\item Descriptor Table - for the Descriptor Area +\item Available Ring - for the Driver Area +\item Used Ring - for the Device Area +\end{itemize} + +\end{note} + \input{split-ring.tex} \chapter{General Initialization And Device Operation}\label{sec:General Initialization And Device Operation} @@ -667,8 +685,8 @@ struct virtio_pci_common_cfg { le16 queue_enable; /* read-write */ le16 queue_notify_off; /* read-only for driver */ le64 queue_desc; /* read-write */ - le64 queue_avail; /* read-write */ - le64 queue_used; /* read-write */ + le64 queue_driver; /* read-write */ + le64 queue_device; /* read-write */ }; \end{lstlisting} @@ -728,13 +746,13 @@ struct virtio_pci_common_cfg { \end{note} \item[\field{queue_desc}] - The driver writes the physical address of Descriptor Table here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. + The driver writes the physical address of Descriptor Area here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. -\item[\field{queue_avail}] - The driver writes the physical address of Available Ring here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. +\item[\field{queue_driver}] + The driver writes the physical address of Driver Area here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. -\item[\field{queue_used}] - The driver writes the physical address of Used Ring here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. +\item[\field{queue_device}] + The driver writes the physical address of Device Area here. See section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues}. \end{description} \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout} @@ -1496,24 +1514,24 @@ All register values are organized as Little Endian. See also p. \ref{sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization}~\nameref{sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization}. } \hline - \mmiodreg{QueueDescLow}{QueueDescHigh}{Virtual queue's Descriptor Table 64 bit long physical address}{0x080}{0x084}{W}{% + \mmiodreg{QueueDescLow}{QueueDescHigh}{Virtual queue's Descriptor Area 64 bit long physical address}{0x080}{0x084}{W}{% Writing to these two registers (lower 32 bits of the address to \field{QueueDescLow}, higher 32 bits to \field{QueueDescHigh}) notifies - the device about location of the Descriptor Table of the queue + the device about location of the Descriptor Area of the queue selected by writing to \field{QueueSel} register. } \hline - \mmiodreg{QueueAvailLow}{QueueAvailHigh}{Virtual queue's Available Ring 64 bit long physical address}{0x090}{0x094}{W}{% + \mmiodreg{QueueDriverLow}{QueueDriverHigh}{Virtual queue's Driver Area 64 bit long physical address}{0x090}{0x094}{W}{% Writing to these two registers (lower 32 bits of the address to \field{QueueAvailLow}, higher 32 bits to \field{QueueAvailHigh}) notifies - the device about location of the Available Ring of the queue + the device about location of the Driver Area of the queue selected by writing to \field{QueueSel}. } \hline - \mmiodreg{QueueUsedLow}{QueueUsedHigh}{Virtual queue's Used Ring 64 bit long physical address}{0x0a0}{0x0a4}{W}{% + \mmiodreg{QueueDeviceLow}{QueueDeviceHigh}{Virtual queue's Device Area 64 bit long physical address}{0x0a0}{0x0a4}{W}{% Writing to these two registers (lower 32 bits of the address to \field{QueueUsedLow}, higher 32 bits to \field{QueueUsedHigh}) notifies - the device about location of the Used Ring of the queue + the device about location of the Device Area of the queue selected by writing to \field{QueueSel}. } \hline @@ -1631,11 +1649,11 @@ The driver will typically initialize the virtual queue in the following way: \item Notify the device about the queue size by writing the size to \field{QueueNum}. -\item Write physical addresses of the queue's Descriptor Table, - Available Ring and Used Ring to (respectively) the +\item Write physical addresses of the queue's Descriptor Area, + Driver Area and Device Area to (respectively) the \field{QueueDescLow}/\field{QueueDescHigh}, - \field{QueueAvailLow}/\field{QueueAvailHigh} and - \field{QueueUsedLow}/\field{QueueUsedHigh} register pairs. + \field{QueueDriverLow}/\field{QueueDriverHigh} and + \field{QueueDeviceLow}/\field{QueueDeviceHigh} register pairs. \item Write 0x1 to \field{QueueReady}. \end{enumerate} @@ -2025,13 +2043,14 @@ struct vq_info_block { be32 res0; be16 index; be16 num; - be64 avail; - be64 used; + be64 driver; + be64 device; }; \end{lstlisting} -\field{desc}, \field{avail} and \field{used} contain the guest addresses for the descriptor table, -available ring and used ring for queue \field{index}, respectively. The actual +\field{desc}, \field{driver} and \field{device} contain the guest +addresses for the descriptor area, +available area and used area for queue \field{index}, respectively. The actual virtqueue size (number of allocated buffers) is transmitted in \field{num}. \devicenormative{\paragraph}{Configuring a Virtqueue}{Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue} |