Re: [PATCH v4 3/6] iommu/vt-d: Implement domain ops for attach_dev_pasid

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, May 18, 2022 at 11:21:17AM -0700, Jacob Pan wrote:
> On VT-d platforms with scalable mode enabled, devices issue DMA requests
> with PASID need to attach PASIDs to given IOMMU domains. The attach
> operation involves the following:
> - Programming the PASID into the device's PASID table
> - Tracking device domain and the PASID relationship
> - Managing IOTLB and device TLB invalidations
> 
> This patch add attach_dev_pasid functions to the default domain ops which
> is used by DMA and identity domain types. It could be extended to support
> other domain types whenever necessary.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
>  drivers/iommu/intel/iommu.c | 72 +++++++++++++++++++++++++++++++++++--
>  1 file changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 1c2c92b657c7..75615c105fdf 100644
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1556,12 +1556,18 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
>  				    u64 addr, unsigned int mask)
>  {
>  	u16 sid, qdep;
> +	ioasid_t pasid;
>  
>  	if (!info || !info->ats_enabled)
>  		return;
>  
>  	sid = info->bus << 8 | info->devfn;
>  	qdep = info->ats_qdep;
> +	pasid = iommu_get_pasid_from_domain(info->dev, &info->domain->domain);

No, a simgple domain can be attached to multiple pasids, all need to
be flushed.

This whole API isn't suitable.

Jason