Re: [PATCH 9/9] iommu: Use fault cookie to store iopf_param

[Baolu Lu]

On 2023/7/13 16:01, Tian, Kevin wrote:
> > From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Thursday, July 13, 2023 11:44 AM
> >
> > On 2023/7/13 11:24, Tian, Kevin wrote:
> > > > From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> > > > Sent: Wednesday, July 12, 2023 11:13 AM
> > > >
> > > > On 2023/7/12 6:02, Jacob Pan wrote:
> > > > > On Tue, 11 Jul 2023 09:06:42 +0800, Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > > > > wrote:
> > > > >
> > > > > > @@ -158,7 +158,7 @@ int iommu_queue_iopf(struct iommu_fault
> > *fault,
> > > > > > struct device *dev)
> > > > > >     	 * As long as we're holding param->lock, the queue can't be
> > > > > > unlinked
> > > > > >     	 * from the device and therefore cannot disappear.
> > > > > >     	 */
> > > > > > -	iopf_param = param->iopf_param;
> > > > > > +	iopf_param = iommu_get_device_fault_cookie(dev, 0);
> > > > > I am not sure I understand how does it know the cookie type is
> > iopf_param
> > > > > for PASID 0?
> > > > >
> > > > > Between IOPF and IOMMUFD use of the cookie, cookie types are
> > different,
> > > > > right?
> > > >
> > > > The fault cookie is managed by the code that delivers or handles the
> > > > faults. The sva and IOMMUFD paths are exclusive.
> > >
> > > what about siov? A siov-capable device can support sva and iommufd
> > > simultaneously.
> >
> > For siov case, the pasid should be global. RID and each pasid are still
> > exclusive, so I don't see any problem. Did I overlook anything?
>
> they are exclusive but it's weird to see some pasids (for sva) on this
> device are tracked by slot#0 while other pasids (for iommufd) occupies
> per-pasid slot.
>
> why not generalizing them given you name it as "per-pasid fault cookie"?

Yeah! Get your point now. At least the partial list should be per-pasid.

Let me invest more time on this.

Best regards,
baolu