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Date: Fri, 8 May 2020 09:39:18 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: baolu.lu@...ux.intel.com, Joerg Roedel <joro@...tes.org>,
ashok.raj@...el.com, Liu Yi L <yi.l.liu@...el.com>,
kevin.tian@...el.com, iommu@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/5] iommu/vt-d: Disable non-recoverable fault
processing before unbind
On 5/8/20 12:55 AM, Jacob Pan wrote:
> On Thu, 7 May 2020 08:55:32 +0800
> Lu Baolu <baolu.lu@...ux.intel.com> wrote:
>
>> When a PASID is used for SVA by the device, it's possible that the
>> PASID entry is cleared before the device flushes all ongoing DMA
>> requests. The IOMMU should ignore the non-recoverable faults caused
>> by these requests.
> Perhaps be more specific, only untranslated requests causes UR.
Yes. Sure!
>
>> Intel VT-d provides such function through the FPD
>> bit of the PASID entry. This sets FPD bit when PASID entry is cleared
>> in the mm notifier and clear it when the pasid is unbound.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
>> ---
>> drivers/iommu/intel-iommu.c | 4 ++--
>> drivers/iommu/intel-pasid.c | 26 +++++++++++++++++++++-----
>> drivers/iommu/intel-pasid.h | 3 ++-
>> drivers/iommu/intel-svm.c | 9 ++++++---
>> 4 files changed, 31 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index d1866c0905b1..7811422b5a68 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -5352,7 +5352,7 @@ static void __dmar_remove_one_dev_info(struct
>> device_domain_info *info) if (info->dev) {
>> if (dev_is_pci(info->dev) && sm_supported(iommu))
>> intel_pasid_tear_down_entry(iommu, info->dev,
>> - PASID_RID2PASID);
>> + PASID_RID2PASID, false);
>>
>> iommu_disable_dev_iotlb(info);
>> domain_context_clear(iommu, info->dev);
>> @@ -5587,7 +5587,7 @@ static void aux_domain_remove_dev(struct
>> dmar_domain *domain, auxiliary_unlink_device(domain, dev);
>>
>> spin_lock(&iommu->lock);
>> - intel_pasid_tear_down_entry(iommu, dev,
>> domain->default_pasid);
>> + intel_pasid_tear_down_entry(iommu, dev,
>> domain->default_pasid, false); domain_detach_iommu(domain, iommu);
>> spin_unlock(&iommu->lock);
>>
>> diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
>> index 7969e3dac2ad..11aef6c12972 100644
>> --- a/drivers/iommu/intel-pasid.c
>> +++ b/drivers/iommu/intel-pasid.c
>> @@ -292,7 +292,20 @@ static inline void pasid_clear_entry(struct
>> pasid_entry *pe) WRITE_ONCE(pe->val[7], 0);
>> }
>>
>> -static void intel_pasid_clear_entry(struct device *dev, int pasid)
>> +static inline void pasid_clear_entry_with_fpd(struct pasid_entry *pe)
>> +{
>> + WRITE_ONCE(pe->val[0], PASID_PTE_FPD);
>> + WRITE_ONCE(pe->val[1], 0);
>> + WRITE_ONCE(pe->val[2], 0);
>> + WRITE_ONCE(pe->val[3], 0);
>> + WRITE_ONCE(pe->val[4], 0);
>> + WRITE_ONCE(pe->val[5], 0);
>> + WRITE_ONCE(pe->val[6], 0);
>> + WRITE_ONCE(pe->val[7], 0);
>> +}
>> +
>> +static void
>> +intel_pasid_clear_entry(struct device *dev, int pasid, bool
>> pf_ignore) {
>> struct pasid_entry *pe;
>>
>> @@ -300,7 +313,10 @@ static void intel_pasid_clear_entry(struct
>> device *dev, int pasid) if (WARN_ON(!pe))
>> return;
>>
>> - pasid_clear_entry(pe);
>> + if (pf_ignore)
>> + pasid_clear_entry_with_fpd(pe);
>> + else
>> + pasid_clear_entry(pe);
>> }
>>
>> static inline void pasid_set_bits(u64 *ptr, u64 mask, u64 bits)
>> @@ -533,8 +549,8 @@ devtlb_invalidation_with_pasid(struct intel_iommu
>> *iommu, qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 -
>> VTD_PAGE_SHIFT); }
>>
>> -void intel_pasid_tear_down_entry(struct intel_iommu *iommu,
>> - struct device *dev, int pasid)
>> +void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct
>> device *dev,
>> + int pasid, bool pf_ignore)
>> {
>> struct pasid_entry *pte;
>> u16 did;
>> @@ -544,7 +560,7 @@ void intel_pasid_tear_down_entry(struct
>> intel_iommu *iommu, return;
>>
>> did = pasid_get_domain_id(pte);
>> - intel_pasid_clear_entry(dev, pasid);
>> + intel_pasid_clear_entry(dev, pasid, pf_ignore);
>>
>> if (!ecap_coherent(iommu->ecap))
>> clflush_cache_range(pte, sizeof(*pte));
>> diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
>> index a41b09b3ffde..e6dd95ffe381 100644
>> --- a/drivers/iommu/intel-pasid.h
>> +++ b/drivers/iommu/intel-pasid.h
>> @@ -15,6 +15,7 @@
>> #define PASID_MAX 0x100000
>> #define PASID_PTE_MASK 0x3F
>> #define PASID_PTE_PRESENT 1
>> +#define PASID_PTE_FPD 2
>> #define PDE_PFN_MASK PAGE_MASK
>> #define PASID_PDE_SHIFT 6
>> #define MAX_NR_PASID_BITS 20
>> @@ -120,7 +121,7 @@ int intel_pasid_setup_nested(struct intel_iommu
>> *iommu, struct iommu_gpasid_bind_data_vtd *pasid_data,
>> struct dmar_domain *domain, int
>> addr_width); void intel_pasid_tear_down_entry(struct intel_iommu
>> *iommu,
>> - struct device *dev, int pasid);
>> + struct device *dev, int pasid, bool
>> pf_ignore); int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned
>> int *pasid); void vcmd_free_pasid(struct intel_iommu *iommu, unsigned
>> int pasid); #endif /* __INTEL_PASID_H */
>> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
>> index 83dc4319f661..9561ba59a170 100644
>> --- a/drivers/iommu/intel-svm.c
>> +++ b/drivers/iommu/intel-svm.c
>> @@ -207,7 +207,8 @@ static void intel_mm_release(struct mmu_notifier
>> *mn, struct mm_struct *mm) */
>> rcu_read_lock();
>> list_for_each_entry_rcu(sdev, &svm->devs, list) {
>> - intel_pasid_tear_down_entry(svm->iommu, sdev->dev,
>> svm->pasid);
>> + intel_pasid_tear_down_entry(svm->iommu, sdev->dev,
>> + svm->pasid, true);
>> intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
>> }
>> rcu_read_unlock();
>> @@ -400,7 +401,8 @@ int intel_svm_unbind_gpasid(struct device *dev,
>> int pasid) sdev->users--;
>> if (!sdev->users) {
>> list_del_rcu(&sdev->list);
>> - intel_pasid_tear_down_entry(iommu, dev,
>> svm->pasid);
>> + intel_pasid_tear_down_entry(iommu, dev,
>> + svm->pasid,
>> false); intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
>> /* TODO: Drain in flight PRQ for the PASID
>> since it
>> * may get reused soon, we don't want to
>> @@ -643,7 +645,8 @@ int intel_svm_unbind_mm(struct device *dev, int
>> pasid)
>> * to use. We have a *shared* PASID table,
>> because it's
>> * large and has to be physically
>> contiguous. So it's
>> * hard to be as defensive as we might like.
>> */
>> - intel_pasid_tear_down_entry(iommu, dev,
>> svm->pasid);
>> + intel_pasid_tear_down_entry(iommu, dev,
>> + svm->pasid,
>> false); intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
>> kfree_rcu(sdev, rcu);
>>
> Reviewed-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
>
Best regards,
baolu
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