[OASIS Issue Tracker] (VIRTIO-139) pci: missing documentation for dealing with 64 bit config fields

[OASIS Issues Tracker <workgroup_mailer@lists.oasis-open.org>]

     [ https://issues.oasis-open.org/browse/VIRTIO-139?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Michael Tsirkin updated VIRTIO-139:
-----------------------------------

    Description: 
pci spec says what width access to use for 32, 16 and 8
bit fields, but does not explicitly say what to do for
32 bit fields. As some implementations might not be able to generate 64 bit accesses,  either allow both 32 and 64 bit
accesses, or require two 32-bit accesses.

  was:
pci spec says what width access to use for 32, 16 and 8
bit fields, but does not explicitly say what to do for
32 bit fields. As some implementations might not be able to generate 64 bit accesses,  either allow both 32 and 64 bit
accesses, or require two 32-bit accesses.


       Proposal: 1427913694-16309-1-git-send-email-mst@redhat.com">http://mid.gmane.org/1427913694-16309-1-git-send-email-mst@redhat.com  (was: Replace text in section
4.1.3.1 Driver Requirements: PCI Device Layout
with the following:

For device configuration access, the driver MUST use 8 bit wide accesses for 8 bit wide fields, 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide and aligned accesses for 32 and 64 bit wide fields.
)

> pci: missing documentation for dealing with 64 bit config fields
> ----------------------------------------------------------------
>
>                 Key: VIRTIO-139
>                 URL: https://issues.oasis-open.org/browse/VIRTIO-139
>             Project: OASIS Virtual I/O Device (VIRTIO) TC
>          Issue Type: Bug
>    Affects Versions: virtio 1.0 cs02
>            Reporter: Michael Tsirkin
>
> pci spec says what width access to use for 32, 16 and 8
> bit fields, but does not explicitly say what to do for
> 32 bit fields. As some implementations might not be able to generate 64 bit accesses,  either allow both 32 and 64 bit
> accesses, or require two 32-bit accesses.



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