This patch links how in a PCI transport a group owner can access group member (PCI VFs) legacy registers using a legacy registers access commands using administration virtqueue infrastructure.
Additionally it extend the PCI notification capability through which a PCI VF device indicates to the driver which PCI BAR region to be used for driver notifications. Fixes: https://github.com/oasis-tcs/virtio-spec/issues/167 Signed-off-by: Parav Pandit <pa...@nvidia.com> --- changelog: v6->v7: - addressed comments from Michael - removed driver normative about I/O BAR emulation as it does not make much sense for the spec - removed references to administration virtqueue - rewrote driver legacy region access without guest and hypervisor wording - added normative for notification region - added normative for PCI IDs for device which support legacy commands v5->v6: - aligned pci capability to 4B as required by PCI spec - added text for the PCI capability for the group member device v4->v5: - split pci transport and generic command section to new patch - removed multiple references to the VF - written the description of the command as generic with member and group device terminology - reflected many section names to remove VF v3->v4: - moved noted to the conformance section details in next patch - removed queue notify address query AQ command on Michael's suggestion, though it is fine. Instead replaced with extending virtio_pci_notify_cap to indicate that legacy queue notifications can be done on the notification location. - fixed spelling errors. - replaced administrative virtqueue to administration virtqueue - added queue notification capability register to indicate legacy q notification supported v2->v3: - adddressed Jason and Michael's comment to split single register access command to common config and device specific commands. - dropped the suggetion to introduce enable/disable command as admin command cap bit already covers it. v1->v2: - addressed comments from Michael - added theory of operation - grammar corrections - removed group fields description from individual commands as it is already present in generic section - added endianness normative for legacy device registers region - renamed the file to drop vf and add legacy prefix - added overview in commit log - renamed subsection to reflect command --- conformance.tex | 1 + transport-pci-legacy-regs.tex | 43 +++++++++++++++++++++++++++++++++++ transport-pci.tex | 2 ++ 3 files changed, 46 insertions(+) create mode 100644 transport-pci-legacy-regs.tex diff --git a/conformance.tex b/conformance.tex index dc00e84..b3f2c92 100644 --- a/conformance.tex +++ b/conformance.tex @@ -267,6 +267,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets} \item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Legacy Interfaces: A Note on PCI Device Layout} \item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtio Device Configuration Layout Detection / Legacy Interface: A Note on Device Layout Detection} \item Section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtqueue Configuration / Legacy Interface: A Note on Virtqueue Configuration} +\item Section \ref{devicenormative:Virtio Transport Options / Virtio Over PCI Bus / Legacy Interface: Group Member Device Configuration Region Access} \item Section \ref{sec:Virtio Transport Options / Virtio Over MMIO / Legacy interface} \item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting the Virtio Revision / Legacy Interfaces: A Note on Setting the Virtio Revision} \item Section \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue / Legacy Interface: A Note on Configuring a Virtqueue} diff --git a/transport-pci-legacy-regs.tex b/transport-pci-legacy-regs.tex new file mode 100644 index 0000000..9559768 --- /dev/null +++ b/transport-pci-legacy-regs.tex @@ -0,0 +1,43 @@ +\subsection{Legacy Interface: Group member device Configuration Region Access}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / Legacy Interface: Group Member Device Configuration Region Access} + +The PCI owner device or the member device or both supports driver notifications using +a notification region defined in the \field{struct virtio_pci_notify_region}. + +In \field{struct virtio_virtio_admin_cmd_legacy_notify_query_entry}, +\field{region} is defined as following: + +\begin{lstlisting} +struct virtio_pci_notify_region { + u8 owner; /* When set to 1, notification region of the owner device */ + u8 bar; /* BAR of the member or owner device */ + u8 padding[2]; + le32 offset; /* Offset within bar. */ +}; +\end{lstlisting} + +The group owner device hardwire VF BAR0 in the SR-IOV Extended capability. + +The group member device does not use PCI BAR0 in various PCI capabilities. + +\devicenormative{\subsubsection}{Legacy Interface: Group Member Device Legacy Configuration Region Access}{Virtio Transport Options / Virtio Over PCI Bus / Legacy Interface: Group Member Device Configuration Region Access} + +When a PCI SR-IOV group owner device supports +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_READ, +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_WRITE, VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ, +VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_WRITE commands, the group owner device MUST +hardwire VF BAR0 in the SR-IOV Extended capability and the group member device +MUST NOT use BAR0 in any of the Virtio Structure PCI Capabilities. + +The group member driver SHOULD use the notification region supplied by the group +owner driver. + +The group owner device or the group member device or both MAY support driver +notifications region. + +For the SR-IOV group type, the owner device supporting +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_READ, +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_WRITE, VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ, +VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_WRITE and VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_QUERY +commands and its member device SHOULD follow the rules for the PCI Device ID, +Revision ID and Subsystem Device ID of the non-transitional devices documented in +section \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery}. diff --git a/transport-pci.tex b/transport-pci.tex index a5c6719..72c78f6 100644 --- a/transport-pci.tex +++ b/transport-pci.tex @@ -1212,3 +1212,5 @@ \subsubsection{Driver Handling Interrupts}\label{sec:Virtio Transport Options / re-examine the configuration space to see what changed. \end{itemize} \end{itemize} + +\input{transport-pci-legacy-regs.tex} -- 2.26.2 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org
