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SubjectRe: [PATCH v2 4/5] iommu/vt-d: Use user privilege for RID2PASID translation
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On 3/20/21 10:54 AM, Lu Baolu wrote:
> When first-level page tables are used for IOVA translation, we use user
> privilege by setting U/S bit in the page table entry. This is to make it
> consistent with the second level translation, where the U/S enforcement
> is not available. Clear the SRE (Supervisor Request Enable) field in the
> pasid table entry of RID2PASID so that requests requesting the supervisor
> privilege are blocked and treated as DMA remapping faults.
>
> Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

We found some devices still require SRE to be set during internal tests.
I will drop this patch from my queue for v5.13 for now.

Best regards,
baolu

> ---
> drivers/iommu/intel/iommu.c | 7 +++++--
> drivers/iommu/intel/pasid.c | 3 ++-
> 2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 868f195f55ff..7354f9ce47d8 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -2494,9 +2494,9 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
> struct device *dev,
> u32 pasid)
> {
> - int flags = PASID_FLAG_SUPERVISOR_MODE;
> struct dma_pte *pgd = domain->pgd;
> int agaw, level;
> + int flags = 0;
>
> /*
> * Skip top levels of page tables for iommu which has
> @@ -2512,7 +2512,10 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
> if (level != 4 && level != 5)
> return -EINVAL;
>
> - flags |= (level == 5) ? PASID_FLAG_FL5LP : 0;
> + if (pasid != PASID_RID2PASID)
> + flags |= PASID_FLAG_SUPERVISOR_MODE;
> + if (level == 5)
> + flags |= PASID_FLAG_FL5LP;
>
> return intel_pasid_setup_first_level(iommu, dev, (pgd_t *)pgd, pasid,
> domain->iommu_did[iommu->seq_id],
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 0bf7e0a76890..dd69df5a188a 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -673,7 +673,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
> * Since it is a second level only translation setup, we should
> * set SRE bit as well (addresses are expected to be GPAs).
> */
> - pasid_set_sre(pte);
> + if (pasid != PASID_RID2PASID)
> + pasid_set_sre(pte);
> pasid_set_present(pte);
> pasid_flush_caches(iommu, pte, pasid, did);
>
>

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