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| -rw-r--r-- | content.tex | 45 |
1 files changed, 31 insertions, 14 deletions
diff --git a/content.tex b/content.tex index 514982f..7f1eecb 100644 --- a/content.tex +++ b/content.tex @@ -963,31 +963,48 @@ respectively. \subsection{PCI Device Discovery}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery} -Any PCI device with Vendor ID 0x1AF4, and Device ID 0x1000 through -0x103F inclusive is a virtio device\footnote{The actual value within this range is ignored -}. - -The Subsystem Device ID indicates which virtio device is -supported by the device, as indicated in section \ref{sec:Device Types}. +Any PCI device with PCI Vendor ID 0x1AF4, and PCI Device ID 0x1000 through +0x103F inclusive is a virtio device. The actual value within this range +indicates which virtio device is supported by the device. +The PCI Device ID is calculated by adding 0xFFF to the Virtio Device ID, +as indicated in section \ref{sec:Device Types}. \devicenormative{\subsubsection}{PCI Device Discovery}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery} -The Subsystem Vendor ID SHOULD reflect -the PCI Vendor ID of the environment (it's currently only used -for informational purposes by the driver). -Non-transitional devices SHOULD have a Revision ID of 1 or higher. +Devices MUST have the PCI Vendor ID 0x1AF4. +Devices MUST have the PCI Device ID calculated by adding 0xFFF +to the Virtio Device ID, +as indicated in section \ref{sec:Device Types}. +For example, the network card device with the Virtio Device ID 1 +has the PCI Device ID 0x1000. + +The PCI Subsystem Vendor ID and the PCI Subsystem Device ID MAY reflect +the PCI Vendor and Device ID of the environment (for informational purposes by the driver). + +Non-transitional devices SHOULD have a PCI Revision ID of 1 or higher. +Non-transitional devices SHOULD have a PCI Subsystem Device ID of 0x40 or higher. This is to reduce the chance of a legacy driver attempting to drive the device. \drivernormative{\subsubsection}{PCI Device Discovery}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery} -All drivers MUST match devices with any Revision ID, this -is to allow devices to be versioned without breaking drivers. +Drivers MUST match devices with the PCI Vendor ID 0x1AF4 and +the PCI Device ID calculated by adding 0xFFF to the Virtio Device ID, +as indicated in section \ref{sec:Device Types}. + +Drivers MUST match devices with any Revision ID, and +MAY match devices with any Subsystem Vendor ID and +Subsystem Device ID, this is to allow devices to be +versioned without breaking drivers. -Drivers MUST match any Revision ID value. +Drivers MUST match any PCI Revision ID value. +Drivers MAY match any PCI Subsystem Vendor ID and any +PCI Subsystem Device ID value. \subsubsection{Legacy Interfaces: A Note on PCI Device Discovery}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery / Legacy Interfaces: A Note on PCI Device Discovery} -Transitional devices MUST have a Revision ID of 0. +Transitional devices MUST have a PCI Revision ID of 0. +Transitional devices MUST have the PCI Subsystem Device ID +matching the Virtio Device ID, as indicated in section \ref{sec:Device Types}. This is to match legacy drivers. |