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

[Baolu Lu]

On 2023/7/12 6:02, Jacob Pan wrote:
> On Tue, 11 Jul 2023 09:06:42 +0800, Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> wrote:
>
> > Remove the static iopf_param pointer from struct iommu_fault_param to
> > save memory.
> >
> > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > ---
> >   include/linux/iommu.h      |  2 --
> >   drivers/iommu/io-pgfault.c | 47 +++++++++++++++++++++++---------------
> >   2 files changed, 29 insertions(+), 20 deletions(-)
> >
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index ffd6fe1317f4..5fe37a7c5a55 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -551,7 +551,6 @@ struct iommu_fault_param {
> >    * struct dev_iommu - Collection of per-device IOMMU data
> >    *
> >    * @fault_param: IOMMU detected device fault reporting data
> > - * @iopf_param:	 I/O Page Fault queue and data
> >    * @fwspec:	 IOMMU fwspec data
> >    * @iommu_dev:	 IOMMU device this device is linked to
> >    * @priv:	 IOMMU Driver private data
> > @@ -564,7 +563,6 @@ struct iommu_fault_param {
> >   struct dev_iommu {
> >   	struct mutex lock;
> >   	struct iommu_fault_param	*fault_param;
> > -	struct iopf_device_param	*iopf_param;
> >   	struct iommu_fwspec		*fwspec;
> >   	struct iommu_device		*iommu_dev;
> >   	void				*priv;
> > diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
> > index 1749e0869f2e..6a3a4e08e67e 100644
> > --- a/drivers/iommu/io-pgfault.c
> > +++ b/drivers/iommu/io-pgfault.c
> > @@ -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.

Best regards,
baolu