On Thu, 27 Jun 2019 20:28:29 +0100
"Dr. David Alan Gilbert (git)" <> wrote:
> From: "Dr. David Alan Gilbert" <>
>
> Define the PCI capability used for enumerating shared memory regions.
>
> Signed-off-by: Dr. David Alan Gilbert <>
> ---
> content.tex | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/content.tex b/content.tex
> index 63e9179..fcf0d81 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -689,6 +689,8 @@ \subsection{Virtio Structure PCI Capabilities}\label{sec:Virtio Transport Option
> #define VIRTIO_PCI_CAP_DEVICE_CFG 4
> /* PCI configuration access */
> #define VIRTIO_PCI_CAP_PCI_CFG 5
> +/* Shared memory region */
> +#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
> \end{lstlisting}
>
> Any other value is reserved for future use.
> @@ -1075,6 +1077,24 @@ \subsubsection{Device-specific configuration}\label{sec:Virtio Transport Options
>
> The \field{offset} for the device-specific configuration MUST be 4-byte aligned.
>
> +\subsubsection{Shared memory capability}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Shared memory capability}
> +
> +Shared memory regions \ref{sec:Basic Facilities of a Virtio
> +Device / Shared Memory Regions} are enumerated on the PCI transport
> +as a sequence of VIRTIO_PCI_CAP_SHARED_MEMORY_CFG capabilities, one per region.
> +
> +The capability is defined by a struct virtio_pci_cap64 and
> +utilises the \field{cap.id} to allow multiple shared memory
> +regions per device.
Maybe add a sentence here
"The identifier in \field{cap.id} does not denote a certain order of
preference; it is only used to uniquely identify a region."
(as per discussion of patch 2)
> +
> +\devicenormative{\paragraph}{Device-specific configuration}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Shared memory capability}
> +
> +The region defined by the combination of the \field {cap.offset},
> +\field {cap.offset_hi}, and \field {cap.length}, \field
> +{cap.length_hi} fields MUST be contained within the declared bar.
> +
> +The \field{cap.id} MUST be unique for any one device instance.
> +
> \subsubsection{PCI configuration access capability}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / PCI configuration access capability}
>
> The VIRTIO_PCI_CAP_PCI_CFG capability
Else, looks good to me.
