RE: [PATCH 1/1] iommu/vt-d: Fix incorrect cache invalidation for mm notification

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, November 17, 2023 5:10 PM
> 
> Commit 6bbd42e2df8f ("mmu_notifiers: call invalidate_range() when
> invalidating TLBs") moved the secondary TLB invalidations into the TLB
> invalidation functions to ensure that all secondary TLB invalidations
> happen at the same time as the CPU invalidation and added a flush-all
> type of secondary TLB invalidation for the batched mode, where a range
> of [0, -1UL) is used to indicates that the range extends to the end of
> the address space.
> 
> However, using an end address of -1UL caused an overflow in the Intel
> IOMMU driver, where the end address was rounded up to the next page.
> As a result, both the IOTLB and device ATC were not invalidated correctly.
> 
> Add a flush all helper function and call it when the invalidation range
> is from 0 to -1UL, ensuring that the entire caches are invalidated
> correctly.
> 
> Fixes: 6bbd42e2df8f ("mmu_notifiers: call invalidate_range() when
> invalidating TLBs")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Huang Ying <ying.huang@xxxxxxxxx>
> Cc: Alistair Popple <apopple@xxxxxxxxxx>
> Tested-by: Luo Yuzhang <yuzhang.luo@xxxxxxxxx> # QAT
> Tested-by: Tony Zhu <tony.zhu@xxxxxxxxx> # DSA
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
>  drivers/iommu/intel/svm.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index 50a481c895b8..588385050a07 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -216,6 +216,27 @@ static void intel_flush_svm_range(struct intel_svm
> *svm, unsigned long address,
>  	rcu_read_unlock();
>  }
> 
> +static void intel_flush_svm_all(struct intel_svm *svm)
> +{
> +	struct device_domain_info *info;
> +	struct intel_svm_dev *sdev;
> +
> +	rcu_read_lock();
> +	list_for_each_entry_rcu(sdev, &svm->devs, list) {
> +		info = dev_iommu_priv_get(sdev->dev);
> +
> +		qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, 0, -1UL,
> 1);

Why setting 'ih' to skip invalidating page structure caches? 

> +		if (info->ats_enabled) {
> +			qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid,
> info->pfsid,
> +						 svm->pasid, sdev->qdep,
> +						 0, 64 - VTD_PAGE_SHIFT);
> +			quirk_extra_dev_tlb_flush(info, 0, 64 -
> VTD_PAGE_SHIFT,
> +						  svm->pasid, sdev->qdep);
> +		}
> +	}
> +	rcu_read_unlock();
> +}
> +
>  /* Pages have been freed at this point */
>  static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
>  					struct mm_struct *mm,
> @@ -223,6 +244,11 @@ static void
> intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
>  {
>  	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
> 
> +	if (start == 0 && end == -1UL) {
> +		intel_flush_svm_all(svm);
> +		return;
> +	}
> +
>  	intel_flush_svm_range(svm, start,
>  			      (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT,
> 0);
>  }
> --
> 2.34.1