Re: [PATCH v8 2/7] iommu: Move global PASID allocation from SVA to core

[Baolu Lu]

On 6/10/23 8:13 PM, Baolu Lu wrote:
> On 6/3/23 2:22 AM, Jacob Pan wrote:
> > +ioasid_t iommu_alloc_global_pasid_dev(struct device *dev)
> > +{
> > +    int ret;
> > +    ioasid_t max;
> > +
> > +    max = dev->iommu->max_pasids;
> > +    /*
> > +     * max_pasids is set up by vendor driver based on number of PASID 
> > bits
> > +     * supported but the IDA allocation is inclusive.
> > +     */
> > +    ret = ida_alloc_range(&iommu_global_pasid_ida, 
> > IOMMU_FIRST_GLOBAL_PASID, max - 1, GFP_KERNEL);
> > +    if (ret < 0)
> > +        return IOMMU_PASID_INVALID;
> > +
> > +    return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_alloc_global_pasid_dev);
>
> "dev->iommu->max_pasids == 0" indicates no pasid support on the device.
> The code should return IOMMU_PASID_INVALID explicitly. Perhaps we can
> make this function like this:
>
> ioasid_t iommu_alloc_global_pasid_dev(struct device *dev)
> {
>          int ret;
>
>          if (!dev->iommu->max_pasids)
>                  return IOMMU_PASID_INVALID;
>
>          /*
>           * max_pasids is set up by vendor driver based on number of 
> PASID bits
>           * supported but the IDA allocation is inclusive.
>           */
>          ret = ida_alloc_range(&iommu_global_pasid_ida, 
> IOMMU_FIRST_GLOBAL_PASID,
>                                dev->iommu->max_pasids - 1, GFP_KERNEL);
>
>          return ret < 0 ? IOMMU_PASID_INVALID : ret;
> }
> EXPORT_SYMBOL_GPL(iommu_alloc_global_pasid_dev);
>
> Other change in this series looks good to me.
>
> I hope I can queue this series including above change as part of my VT-d
> update for v6.5 to Joerg if no objection.
>
> Let's try to re-enable this key feature of Intel idxd driver in v6.5.

This series didn't pass my test.

The first time when I run "idxd_ktest.sh -c 1 -t 1 -i 100 -m shared", it
passed. But when I run it again, the idxd hardware operation resulted in
timed-out issues.

I have removed this series from my queue.

Best regards,
baolu