RE: [Xen-devel] [PATCH] [VTD] Remove PCI device enumeration for dom0 in Xen

["Han, Weidong" <weidong.han@xxxxxxxxx>]

Keir Fraser wrote:
> On 22/10/08 13:38, "Espen Skoglund" <espen.skoglund@xxxxxxxxxxxxx>
> wrote: 
> 
>>> Xen 3.3 should continue to work with older dom0 kernels. However,
>>> now that iommu is *disabled* by default, will this mean that it
>>> would continue to work with older dom0 kernels so long as iommu is
>>> not enabled on the Xen command line? This should be tested and
>>> confirmed with this patch applied.  If so, I would accept it.
>> 
>> Users of pci_lock_pdev() and pci_lock_domain_pdev() would not be able
>> to find the PCI device unless it has been registered by dom0.  Apart
>> from the iommu code, the only user affected would be the MSI code
>> which looks up the PCI device before enabling MSIs on it.  As such,
>> you would not be able to enable MSIs if you have an old dom0 kernel.
> 
> Is there any disadvantage to keeping this legacy code in Xen, apart
> from it annoyingly sitting there?
> 

 At present, I don't see any other disadvantage on functionality, apart
from it annoyingly sitting there and it allocates two pdev for the same
bdf.

Regards,
Weidong


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