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diff --git a/content.tex b/content.tex index d68cfaf..b2ebbe2 100644 --- a/content.tex +++ b/content.tex @@ -691,6 +691,8 @@ The fields are interpreted as follows: #define VIRTIO_PCI_CAP_PCI_CFG 5 /* Shared memory region */ #define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8 +/* Vendor-specific data */ +#define VIRTIO_PCI_CAP_VENDOR_CFG 9 \end{lstlisting} Any other value is reserved for future use. @@ -1099,6 +1101,80 @@ The region defined by the combination of the \field {cap.offset}, The \field{cap.id} MUST be unique for any one device instance. +\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{Vendor data capability}\label{sec:Virtio +Transport Options / Virtio Over PCI Bus / PCI Device Layout / +Vendor data capability} + +The optional Vendor data capability allows the device to present +vendor-specific data to the driver, without +conflicts, for debugging and/or reporting purposes, +and without conflicting with standard functionality. + +This capability augments but does not replace the standard +subsystem ID and subsystem vendor ID fields +(offsets 0x2C and 0x2E in the PCI configuration space header) +as specified by \hyperref[intro:PCI]{[PCI]}. + +Vendor data capability is enumerated on the PCI transport +as a VIRTIO_PCI_CAP_VENDOR_CFG capability. + +The capability has the following structure: +\begin{lstlisting} +struct virtio_pci_vndr_data { + u8 cap_vndr; /* Generic PCI field: PCI_CAP_ID_VNDR */ + u8 cap_next; /* Generic PCI field: next ptr. */ + u8 cap_len; /* Generic PCI field: capability length */ + u8 cfg_type; /* Identifies the structure. */ + u16 vendor_id; /* Identifies the vendor-specific format. */ + /* For Vendor Definition */ + /* Pads structure to a multiple of 4 bytes */ + /* Reads must not have side effects */ +}; +\end{lstlisting} + +Where \field{vendor_id} identifies the PCI-SIG assigned Vendor ID +as specified by \hyperref[intro:PCI]{[PCI]}. + +Note that the capability size is required to be a multiple of 4. + +To make it safe for a generic driver to access the capability, +reads from this capability MUST NOT have any side effects. + +\devicenormative{\subsection}{Vendor data capability}{Virtio +Transport Options / Virtio Over PCI Bus / PCI Device Layout / +Vendor data capability} + +Devices CAN present \field{vendor_id} that does not match +either the PCI Vendor ID or the PCI Subsystem Vendor ID. + +Devices CAN present multiple Vendor data capabilities with +either different or identical \field{vendor_id} values. + +The value \field{vendor_id} MUST NOT equal 0x1AF4. + +The size of the Vendor data capability MUST be a multiple of 4 bytes. + +Reads of the Vendor data capability by the driver MUST NOT have any +side effects. + +\drivernormative{\subsection}{Vendor data capability}{Virtio +Transport Options / Virtio Over PCI Bus / PCI Device Layout / +Vendor data capability} + +The driver SHOULD NOT use the Vendor data capability except +for debugging and reporting purposes. + +The driver MUST qualify the \field{vendor_id} before +interpreting or writing into the Vendor data capability. + \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 |