RE: [PATCH v8 09/10] iommufd: Add data structure for Intel VT-d stage-1 cache invalidation

[Tian, Kevin]

> From: Tian, Kevin
> Sent: Thursday, December 28, 2023 2:38 PM
> 
> > From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> > Sent: Thursday, December 28, 2023 12:14 AM
> > +/**
> > + * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
> > + *                                       (IOMMU_HWPT_INVALIDATE_DATA_VTD_S1)
> > + * @addr: The start address of the range to be invalidated. It needs to
> > + *        be 4KB aligned.
> > + * @npages: Number of contiguous 4K pages to be invalidated.
> > + * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
> > + * @hw_error: One of enum iommu_hwpt_vtd_s1_invalidate_error
> > + *
> > + * The Intel VT-d specific invalidation data for user-managed stage-1 cache
> > + * invalidation in nested translation. Userspace uses this structure to
> > + * tell the impacted cache scope after modifying the stage-1 page table.
> > + *
> > + * Invalidating all the caches related to the page table by setting @addr
> > + * to be 0 and @npages to be U64_MAX.
> > + *
> > + * The device TLB will be invalidated automatically if ATS is enabled.
> > + *
> > + * The @hw_error is meaningful when the entry is handled by the kernel.
> > + * Check the entry_num output of IOMMU_HWPT_INVALIDATE ioctl to
> > know the
> > + * handled entries. @hw_error only covers the errors detected by
> hardware.
> > + * The software detected errors would go through the normal ioctl errno.
> > + */
> 
> * An entry is considered 'handled' after it passes the audit and submitted
> * to the IOMMU by the underlying driver. Check the @entry_num output of
> * struct iommu_hwpt_invalidate for the number of handled entries. A
> 'handled'
> * request may still fail in hardware for various reasons, e.g. due to timeout
> * on waiting for device response upon a device TLB invalidation request. In
> * such case the hardware error info is reported in the @hw_error field of the
> * handled entry.

with that:

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>