[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [PATCH] content: add vendor specific cfg type
On Mon, Oct 28, 2019 at 06:55:42AM -0400, Michael S. Tsirkin wrote: > Vendors might want to add their own capability > in the PCI capability list. However, Virtio already > uses the vendor specific capability ID (0x09) > for its own purposes. > > Provide a structure for vendor specific extensions. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/62 > --- > content.tex | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 80 insertions(+) > > diff --git a/content.tex b/content.tex > index b1ea9b9..8a79b03 100644 > --- a/content.tex > +++ b/content.tex > @@ -691,6 +691,8 @@ \subsection{Virtio Structure PCI Capabilities}\label{sec:Virtio Transport Option > #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 +1101,84 @@ \subsubsection{Shared memory capability}\label{sec:Virtio Transport Options / Vi > > 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} > + > +The device SHOULD present the PCI subsystem vendor ID matching > +the device vendor, at offset 0x2C in its PCI configuration space > +header. > + > +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 > -- > MST
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]