Re: [PATCH 1/1] iommu/amd: Fix PASID format in INVALIDATE_IOTLB_PAGES command

[Suravee Suthikulpanit]

On 3/4/2014 10:53 AM, Suravee Suthikulpanit wrote:
> On 3/4/2014 8:12 AM, Joerg Roedel wrote:
> > On Wed, Feb 26, 2014 at 03:49:31PM -0600,
> > suravee.suthikulpanit@xxxxxxx wrote:
> > > From: Jay Cornwall <jay.cornwall@xxxxxxx>
> > >
> > > This patch corrects the PASID format in the INVALIDATE_IOTLB_PAGES
> > > command, which was caused by incorrect information in
> > > the AMD IOMMU Architectural Specification v2.01 document.
> > >
> > >      Incorrect format:
> > >           cmd->data[0][16:23] = PASID[7:0]
> > >           cmd->data[1][16:27] = PASID[19:8]
> > >
> > >       Correct format:
> > >           cmd->data[0][16:23] = PASID[15:8]
> > >           cmd->data[1][16:23] = PASID[7:0]
> > >
> > > However, this does not affect the IOMMUv2 hardware implementation,
> > > and has been corrected since version 2.02 of the specification
> > > (available through AMD NDA).
> > >
> > > Signed-off-by: Jay Cornwall <jay.cornwall@xxxxxxx>
> > > Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> >
> > Applied, thanks.
> >
> > Does this mean that PASIDs are only 16 bits wide now from the former 20
> > bits?
>
> Thank you Joerg. The specification also state that this command format
> does not support the maximum size of the PASID field. However, other
> commands seem to still support 20-bit PASID.
>
> Suravee

Actually, just thinking about this again, even though we don't have 
systems with 20-bit PASID yet (only up-to 16-bit), but for future proof, 
we should add another logic to make sure that this logic won't try to 
use the 20-bit PASID with this version of the command.  I'll send out 
another patch soon.

Suravee

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