Messages in this thread | | | Date | Mon, 25 Jul 2022 17:33:05 +0800 | Subject | Re: [PATCH v10 08/12] iommu/sva: Refactoring iommu_sva_bind/unbind_device() | From | Baolu Lu <> |
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Hi Jean,
On 2022/7/25 15:39, Jean-Philippe Brucker wrote: > On Sun, Jul 24, 2022 at 09:48:15PM +0800, Baolu Lu wrote: >> /* >> * iommu_detach_device_pasid() - Detach the domain from pasid of device >> * @domain: the iommu domain. >> * @dev: the attached device. >> * @pasid: the pasid of the device. >> * >> * The @domain must have been attached to @pasid of the @dev with >> * iommu_detach_device_pasid(). >> */ >> void iommu_detach_device_pasid(struct iommu_domain *domain, struct device >> *dev, >> ioasid_t pasid) >> { >> struct iommu_group *group = iommu_group_get(dev); >> struct group_pasid *param; >> >> mutex_lock(&group->mutex); >> domain->ops->set_dev_pasid(group->blocking_domain, dev, pasid); > Please also pass the old domain to this detach() function, so that the > IOMMU driver doesn't have to keep track of them internally.
The iommu core provides the interface to retrieve attached domain with a {device, pasid} pair. Therefore in the smmuv3 driver, the set_dev_pasid could do like this:
+static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t id) +{ + int ret = 0; + struct mm_struct *mm; + struct iommu_sva *handle; + + /* + * Detach the domain if a blocking domain is set. Check the + * right domain type once the IOMMU driver supports a real + * blocking domain. + */ + if (!domain || domain->type == IOMMU_DOMAIN_UNMANAGED) { + struct pasid_iommu *param; + + param = iommu_device_pasid_param(dev, id); + if (!param || !param->domain) + return -EINVAL; + arm_smmu_sva_block_dev_pasid(param->domain, dev, id); + + return 0; + } + + mm = domain->mm; + mutex_lock(&sva_lock); + handle = __arm_smmu_sva_bind(dev, mm); + if (IS_ERR(handle)) + ret = PTR_ERR(handle); + mutex_unlock(&sva_lock); + + return ret; +}
The check of "(!domain || domain->type == IOMMU_DOMAIN_UNMANAGED)" looks odd, but could get cleaned up after a real blocking domain is added. Then, we can simply check "domain->type == IOMMU_DOMAIN_BLOCKING".
> In addition to clearing contexts, detach() also needs to invalidate TLBs, > and for that the SMMU driver needs to know the old ASID (!= PASID) that > was used by the context descriptor.
Best regards, baolu
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