Re: [PATCH 1/1] x86/tboot: Don't disable swiotlb when iommu is forced on

Konrad Rzeszutek Wilk
2020-11-25T16:26:32Z

On Wed, Nov 25, 2020 at 03:51:30PM +0000, Will Deacon wrote:
> Hi Konrad,
>
> On Wed, Nov 25, 2020 at 10:41:53AM -0500, Konrad Rzeszutek Wilk wrote:
> > On Wed, Nov 25, 2020 at 02:05:15PM +0000, Will Deacon wrote:
> > > On Wed, 25 Nov 2020 09:41:24 +0800, Lu Baolu wrote:
> > > > After commit 327d5b2fee91c ("iommu/vt-d: Allow 32bit devices to uses DMA
> > > > domain"), swiotbl could also be used for direct memory access if IOMMU
> > > > is enabled but a device is configured to pass through the DMA translation.
> > > > Keep swiotlb when IOMMU is forced on, otherwise, some devices won't work
> > > > if "iommu=pt" kernel parameter is used.
> > >
> > > Applied to arm64 (for-next/iommu/fixes), thanks!
> > >
> > > [1/1] x86/tboot: Don't disable swiotlb when iommu is forced on
> > > https://git.kernel.org/arm64/c/e2be2a833ab5
> >
> > But tboot never ran on ARM. It is a Intel specifc.
> >
> > I think either me or Thomas should take this patch.
>
> FWIW, I did check with Thomas before I picked it up. I know it looks weird
> going via arm64, but that's only because I'm temporarily handling the IOMMU
> tree there (including vt-d changes) while Joerg is away. Since this fixes a
> vt-d regression, I thought I'd pick it up along with the other IOMMU fixes I
> have queued for -rc6.
>

Aah, I missed the memo :-)

> That said, if you insist, then I can revert it. I'm really only trying to
> help here.

Nah. Enjoy picking up patches!

Thanks!
>
> Will