Messages in this thread | | | Date | Thu, 2 Mar 2023 22:06:40 +0800 | Subject | Re: [PATCH 1/4] iommu/vt-d: Implement set device pasid op for default domain | From | Baolu Lu <> |
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On 2023/3/2 8:59, Jacob Pan wrote: > On VT-d platforms, legacy DMA requests without PASID use device’s > default domain, where RID_PASID is always attached. Device drivers > can then use the DMA API for all in-kernel DMA on the RID. > > Ideally, devices capable of using ENQCMDS can also transparently use the > default domain, consequently DMA API. However, VT-d architecture > dictates that the PASID used by ENQCMDS must be different from the > RID_PASID value. > > To provide support for transparent use of DMA API with non-RID_PASID > value, this patch implements the set_dev_pasid() function for the > default domain. The idea is that device drivers wishing to use ENQCMDS > to submit work on buffers mapped by DMA API will call > iommu_attach_device_pasid() beforehand. > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > --- > drivers/iommu/intel/iommu.c | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 10f657828d3a..a0cb3bc851ac 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -4665,6 +4665,10 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid) > case IOMMU_DOMAIN_SVA: > intel_svm_remove_dev_pasid(dev, pasid); > break; > + case IOMMU_DOMAIN_DMA: > + case IOMMU_DOMAIN_DMA_FQ: > + case IOMMU_DOMAIN_IDENTITY: > + break; > default: > /* should never reach here */ > WARN_ON(1); > @@ -4675,6 +4679,33 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid) > intel_pasid_tear_down_entry(iommu, dev, pasid, false); > } > > +static int intel_iommu_set_dev_pasid(struct iommu_domain *domain, > + struct device *dev, ioasid_t pasid) > +{ > + struct device_domain_info *info = dev_iommu_priv_get(dev); > + struct dmar_domain *dmar_domain = to_dmar_domain(domain); > + struct intel_iommu *iommu = info->iommu; > + int ret = 0; > + > + if (!sm_supported(iommu) || !info)
@info has been referenced. !info check makes no sense.
Add pasid_supported(iommu).
Do you need to check whether the domain is compatible for this rid pasid?
> + return -ENODEV; > + > + if (WARN_ON(pasid == PASID_RID2PASID)) > + return -EINVAL;
Add a call to domain_attach_iommu() here to get a refcount of the domain ID. And call domain_detach_iommu() in intel_iommu_remove_dev_pasid().
> + > + if (hw_pass_through && domain_type_is_si(dmar_domain)) > + ret = intel_pasid_setup_pass_through(iommu, dmar_domain, > + dev, pasid); > + else if (dmar_domain->use_first_level) > + ret = domain_setup_first_level(iommu, dmar_domain, > + dev, pasid); > + else > + ret = intel_pasid_setup_second_level(iommu, dmar_domain, > + dev, pasid); > + > + return ret; > +}
Do you need to consider pasid cache invalidation?
> + > const struct iommu_ops intel_iommu_ops = { > .capable = intel_iommu_capable, > .domain_alloc = intel_iommu_domain_alloc, > @@ -4702,6 +4733,7 @@ const struct iommu_ops intel_iommu_ops = { > .iova_to_phys = intel_iommu_iova_to_phys, > .free = intel_iommu_domain_free, > .enforce_cache_coherency = intel_iommu_enforce_cache_coherency, > + .set_dev_pasid = intel_iommu_set_dev_pasid, > } > }; >
Best regards, baolu
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