Re: [PATCH v2] iommu/arm: Add module parameter to set msi iova address

[Vennila Megavannan]

Sure, that's a great suggestion, I'll rework on the patch and post again.

Vennila

On 9/21/2020 1:45 PM, Will Deacon wrote:
> On Mon, Sep 14, 2020 at 11:13:07AM -0700, Vennila Megavannan wrote:
> > From: Srinath Mannam <srinath.mannam@xxxxxxxxxxxx>
> >
> > Add provision to change default value of MSI IOVA base to platform's
> > suitable IOVA using module parameter. The present hardcoded MSI IOVA base
> > may not be the accessible IOVA ranges of platform.
> >
> > If any platform has the limitaion to access default MSI IOVA, then it can
> > be changed using "arm-smmu.msi_iova_base=0xa0000000" command line argument.
> >
> > Signed-off-by: Srinath Mannam <srinath.mannam@xxxxxxxxxxxx>
> > Co-developed-by: Vennila Megavannan <vemegava@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Vennila Megavannan <vemegava@xxxxxxxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 ++++-
> >   drivers/iommu/arm/arm-smmu/arm-smmu.c       | 5 ++++-
> >   2 files changed, 8 insertions(+), 2 deletions(-)
> This feels pretty fragile. Wouldn't it be better to realise that there's
> a region conflict with iommu_dma_get_resv_regions() and move the MSI window
> accordingly at runtime?
>
> Will