Messages in this thread | | | Date | Mon, 21 Mar 2022 11:33:54 +0000 | From | Jean-Philippe Brucker <> | Subject | Re: [PATCH RFC 06/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces |
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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.
Thanks, Jean
> The device should > + * not be issuing any more transaction for this PASID. All outstanding page > + * requests for this PASID must have been flushed to the IOMMU. > + */ > +void iommu_sva_unbind_device(struct iommu_sva *handle) > +{ > + struct device *dev = handle->dev; > + struct iommu_domain *domain = handle->domain; > + struct mm_struct *mm = domain->sva_cookie; > + > + iommu_detach_device_pasid(domain, dev, mm->pasid); > + iommu_domain_free(domain); > + kfree(handle); > +} > +EXPORT_SYMBOL_GPL(iommu_sva_unbind_device); > + > +u32 iommu_sva_get_pasid(struct iommu_sva *handle) > +{ > + return handle->pasid; > +} > +EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
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