Re: [PATCH 2/2] iommu: Fix the domain type checks when default_domain is set

[Shivaprasad G Bhat]

On 1/25/24 21:22, Jason Gunthorpe wrote:
> On Thu, Jan 25, 2024 at 06:08:52AM -0600, Shivaprasad G Bhat wrote:
> > On PPC64, the iommu_ops.def_domain_type() is not defined and
> > CONFIG_IOMMU_DMA not enabled. With commit 0f6a90436a57 ("iommu: Do not
> > use IOMMU_DOMAIN_DMA if CONFIG_IOMMU_DMA is not enabled"), the
> > iommu_get_default_domain_type() return IOMMU_DOMAIN_IDENTITY. With
> > commit 2ad56efa80db ("powerpc/iommu: Setup a default domain and remove
> > set_platform_dma_ops"), the defaule_domain is set wih the type being
> > PLATFORM. With these two changes, iommu_group_alloc_default_domain()
> > ends up returning the NULL(with recent changes, ERR_PTR(-EINVAL))
> > leading to iommu_probe_device() failure and the device has no
> > iommu_group set in effect. Subsequently, the bind to vfio(VFIO_IOMMU)
> > fail as the iommu_group is not set for the device.
> >
> > Make the iommu_get_default_domain_type() to take default_domain->type
> > into consideration along with default_domain_type() and fix
> > iommu_group_alloc_default_domain() to not error out if the requested
> > type is same as default domain type.
> >
> > Fixes: 2ad56efa80db ("powerpc/iommu: Setup a default domain and remove set_platform_dma_ops")
> > Fixes: 0f6a90436a57 ("iommu: Do not use IOMMU_DOMAIN_DMA if CONFIG_IOMMU_DMA is not enabled")
> > Signed-off-by: Shivaprasad G Bhat <sbhat@xxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/iommu.c |   14 ++++++++++----
> >   1 file changed, 10 insertions(+), 4 deletions(-)
> Are you OK with this version?
>
> https://lore.kernel.org/linux-iommu/20240123174905.GS50608@xxxxxxxx/
>
> ?
>
> I think it does the same thing

Yes, This works. I see a very minor difference of default_domain->type 
is given

precedence over def_domain_type(). Please keep me CC when you post this 
fix, I'll

test it with any(?) other changes if coming along with it.


Thanks,

Shivaprasad

> Jason