diff options
| author | mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652> | 2015-10-21 14:20:27 +0000 |
|---|---|---|
| committer | mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652> | 2015-10-21 14:20:27 +0000 |
| commit | f8d44600b775ffdce8be566c9c5764022ef2c3dc (patch) | |
| tree | 3a76e3bc1af27e852234fbe17ba3ba9d6f9ecd1a | |
| parent | ff6b2bb653ae98cd0e71523d9c82f908bc95f035 (diff) | |
pci: clarify configuration access capability rules
The point of the configuration access capability is to enable
access to other capabilities. The intent never was to allow
writes to a random place within device BARs.
Limiting drivers simplifies devices - and devices can always
add another capability if drivers ever want to access
some other range.
This resolves VIRTIO-145.
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Accepted by electronic ballot:
https://www.oasis-open.org/apps/org/workgroup/virtio/ballot.php?id=2865
git-svn-id: https://tools.oasis-open.org/version-control/svn/virtio/branches/v1.0@547 0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652
| -rw-r--r-- | content.tex | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/content.tex b/content.tex index e054919..941daa6 100644 --- a/content.tex +++ b/content.tex @@ -1132,6 +1132,7 @@ The virtio device configuration layout includes several structures: \item Notifications \item ISR Status \item Device-specific configuration (optional) +\item PCI configuration access \end{itemize} Each structure can be mapped by a Base Address register (BAR) belonging to @@ -1578,6 +1579,12 @@ at BAR selected by \field{cap.bar} and store the first \field{cap.length} bytes The driver MUST NOT write a \field{cap.offset} which is not a multiple of \field{cap.length} (ie. all accesses MUST be aligned). +The driver MUST NOT read or write \field{pci_cfg_data} +unless \field{cap.bar}, \field{cap.length} and \field{cap.offset} +address \field{cap.length} bytes within a BAR range +specified by some other Virtio Structure PCI Capability +of type other than \field{VIRTIO_PCI_CAP_PCI_CFG}. + \subsubsection{Legacy Interfaces: A Note on PCI Device Layout}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Legacy Interfaces: A Note on PCI Device Layout} Transitional devices MUST present part of configuration |