Re: [Xen-devel] [PATCH][VTD] pci mmcfg patch for x86-64 - version 2

[Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>]

I see that all the special pci mmcfg stuff has been put under the
x86_64 tree.  However, most of it is generic x86.  Why not make the
code mostly generic x86 and let the x86_32 specific part fail
gracefully (as in: mmcfg not configured properly)?  Support for x86_32
can then later be added without requiring code duplication or
restructuring.

        eSk


[Allen M Kay]
> Fixes made in version 2:
> 1) Use PML4[257] for ioremap of PCI mmcfg.  As full 16-bit segment
>    support would require 44-bits.  Since each slot only has 39-bits,
>    we support 2048 PCI segments for now.  This can be easily
>    expanded if deemed necessary in the future.

> 2) Integrated PCI mmcfg access with existing PCI config interface
>    for x86_64.  Use MMCFG interface if offset is greater than 256.

> Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>

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