Re: [PATCH v13 1/6] iommu: Deprecate Intel and AMD cmdline methods to enable strict mode

[John Garry]

On 17/06/2021 20:01, Robin Murphy wrote:
> >               DMA.
> > -        strict [Default Off]
> > +        strict [Default Off] [Deprecated, use iommu.strict instead]
> >               With this option on every unmap_single operation will
> >               result in a hardware IOTLB flush operation as opposed
> >               to batching them for performance.
>
> FWIW I'd be inclined to replace both whole descriptions with just 
> something like "Deprecated, equivalent to iommu.strict=1".
>
> > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> > index 46280e6e1535..9f3096d650aa 100644
> > --- a/drivers/iommu/amd/init.c
> > +++ b/drivers/iommu/amd/init.c
> > @@ -3098,8 +3098,10 @@ static int __init parse_amd_iommu_intr(char *str)
> >   static int __init parse_amd_iommu_options(char *str)
> >   {
> >       for (; *str; ++str) {
> > -        if (strncmp(str, "fullflush", 9) == 0)
> > +        if (strncmp(str, "fullflush", 9) == 0) {
> > +            pr_warn("amd_iommu=fullflush deprecated; use iommu.strict 
> > instead\n");
>
> Nit: maybe we should spell out "...use <option>=1 instead" in all of 
> these messages just in case anyone takes them literally?


> (I'm not sure 
> the options parse correctly with no argument)

I don't think they do.

But I'll take both suggestions on board.

> Either way,
>
> Acked-by: Robin Murphy <robin.murphy@xxxxxxx>

Cheers!