Messages in this thread | | | Date | Wed, 30 Mar 2022 12:35:40 +0800 | Subject | Re: [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA | From | Lu Baolu <> |
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On 2022/3/30 5:38, Jacob Pan wrote: >> +static struct iommu_domain * >> +iommu_sva_alloc_domain(struct device *dev, struct mm_struct *mm) >> +{ >> + struct bus_type *bus = dev->bus; >> + struct iommu_sva_cookie *cookie; >> + struct iommu_domain *domain; >> + void *curr; >> + >> + if (!bus || !bus->iommu_ops) >> + return NULL; >> + >> + cookie = kzalloc(sizeof(*cookie), GFP_KERNEL); >> + if (!cookie) >> + return NULL; >> + >> + domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_SVA); >> + if (!domain) >> + goto err_domain_alloc; >> + >> + cookie->mm = mm; >> + cookie->pasid = mm->pasid; > How do you manage the mm life cycle? do you require caller take mm reference? > Or this should be limited to the current mm? >
The existing sva_bind() interface requires the caller to take the mm reference before calling it. So mm is safe during sva bind() and unbind().
drivers/iommu/iommu.c: /** * iommu_sva_bind_device() - Bind a process address space to a device * @dev: the device * @mm: the mm to bind, caller must hold a reference to it * @drvdata: opaque data pointer to pass to bind callback * * Create a bond between device and address space, allowing the device to access * the mm using the returned PASID. If a bond already exists between @device and * @mm, it is returned and an additional reference is taken. Caller must call * iommu_sva_unbind_device() to release each reference. * * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to * initialize the required SVA features. * * On error, returns an ERR_PTR value. */ struct iommu_sva * iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
Best regards, baolu
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