Messages in this thread | | | Date | Tue, 22 Mar 2022 12:29:40 +0800 | Subject | Re: [PATCH RFC 06/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces | From | Lu Baolu <> |
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On 2022/3/21 19:33, Jean-Philippe Brucker wrote: > On Sun, Mar 20, 2022 at 02:40:25PM +0800, Lu Baolu wrote: >> diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c >> index 106506143896..47cf98e661ff 100644 >> --- a/drivers/iommu/iommu-sva-lib.c >> +++ b/drivers/iommu/iommu-sva-lib.c >> @@ -3,6 +3,8 @@ >> * Helpers for IOMMU drivers implementing SVA >> */ >> #include <linux/mutex.h> >> +#include <linux/iommu.h> >> +#include <linux/slab.h> >> #include <linux/sched/mm.h> >> >> #include "iommu-sva-lib.h" >> @@ -69,3 +71,101 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid) >> return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero); >> } >> EXPORT_SYMBOL_GPL(iommu_sva_find); >> + >> +static struct iommu_domain *iommu_sva_domain_alloc(struct device *dev) >> +{ >> + struct bus_type *bus = dev->bus; >> + struct iommu_domain *domain; >> + >> + if (!bus || !bus->iommu_ops) >> + return NULL; >> + >> + domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_SVA); >> + if (domain) >> + domain->type = IOMMU_DOMAIN_SVA; >> + >> + return domain; >> +} >> + >> +/** >> + * 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. > This is not true anymore, we return a different structure for each call. > >> 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) >> +{ >> + int ret = -EINVAL; >> + struct iommu_sva *handle; >> + struct iommu_domain *domain; >> + >> + handle = kzalloc(sizeof(*handle), GFP_KERNEL); >> + if (!handle) >> + return ERR_PTR(-ENOMEM); >> + >> + ret = iommu_sva_alloc_pasid(mm, 1, (1U << dev->iommu->pasid_bits) - 1); >> + if (ret) >> + goto out; >> + >> + domain = iommu_sva_domain_alloc(dev); >> + if (!domain) { >> + ret = -ENOMEM; >> + goto out; >> + } >> + domain->sva_cookie = mm; >> + >> + ret = iommu_attach_device_pasid(domain, dev, mm->pasid); >> + if (ret) >> + goto out_free_domain; >> + >> + handle->dev = dev; >> + handle->domain = domain; >> + handle->pasid = mm->pasid; >> + >> + return handle; >> + >> +out_free_domain: >> + iommu_domain_free(domain); >> +out: >> + kfree(handle); >> + >> + return ERR_PTR(ret); >> +} >> +EXPORT_SYMBOL_GPL(iommu_sva_bind_device); >> + >> +/** >> + * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device >> + * @handle: the handle returned by iommu_sva_bind_device() >> + * >> + * Put reference to a bond between device and address space. > Same here. But I'd prefer keeping the old behavior so device drivers don't > have to keep track of {dev, mm} pairs themselves.
Okay. Thank you for pointing this out. Let me figure it out in the next version.
Best regards, baolu
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