WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] [PATCH 1/2][VTD] pci mmconfig support to be used for ATS

To: Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH 1/2][VTD] pci mmconfig support to be used for ATS
From: "Kay, Allen M" <allen.m.kay@xxxxxxxxx>
Date: Thu, 20 Nov 2008 12:04:41 -0800
Accept-language: en-US
Acceptlanguage: en-US
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Han, Weidong" <weidong.han@xxxxxxxxx>, "Cui, Dexuan" <dexuan.cui@xxxxxxxxx>
Delivery-date: Thu, 20 Nov 2008 12:05:17 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <18725.20450.88621.702587@xxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <57C9024A16AD2D4C97DC78E552063EA35C4BC7A4@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <18725.20450.88621.702587@xxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AclLBtagsB9bhRy5T22Bnx0Jrd6zgAAQ9nSg
Thread-topic: [Xen-devel] [PATCH 1/2][VTD] pci mmconfig support to be used for ATS
>
>  - Use the regular PCI config access functions, and if accesses above
>    the regular 255 registers are detected then use mmio (if
>    available) for accesses.  The regular PCI configuration space is
>    still always accessible using standard mechanisms.
>
>  - Introduce pci_ops integrated properly into Xen internals.  You may
>    even want to pci_ops on a per device or per bus basis.
>

I will look into to see which of the above method is cleaner to implement.

>I also see that you've modified struct pci_dev to accomomodate for
>specifc ATS needs.  The 'bus' and 'devfn' fields have been made non
>constant.  They were marked as 'const' for a reason --- modifying them
>leads to race conditions.  Further, you don't actually allocate the
>pci_dev using the proper allocate function.  If you don't want the ATS
>unit to be treated as a PCI device in Xen then don't use struct
>pci_dev.  Create a separate struct ats_unit containing the fields you
>need instead.
>

I will define a new ATS structure instead of using the existing pci_dev 
structure so that it will not disturb existing use model for pci_dev structure.

Allen
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel