Messages in this thread | | | Date | Fri, 10 Mar 2023 10:10:56 +0800 | Subject | Re: [PATCH 04/12] iommufd: Pass parent hwpt and user_data to iommufd_hw_pagetable_alloc() | From | Baolu Lu <> |
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On 3/9/23 4:09 PM, Yi Liu wrote: > Nested translation has stage-1 and stage-2 page tables. A stage-1 page > table is managed by user space, and it needs to work with a stage-2 page > table, which is a parent hwpt for the stage-1 hwpt. > > iommu core already supports accepting parent iommu_domain and user_data > to allocate an iommu_domain. This makes iommufd_hw_pagetable_alloc() to > accept the parent hwpt and user_data, and relays them to iommu core, to > prepare for supporting hw_pagetable allocation with user_data. > > Also, add a parent pointer in struct iommufd_hw_pagetable for taking and > releasing its refcount. > > Co-developed-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > --- > drivers/iommu/iommufd/device.c | 2 +- > drivers/iommu/iommufd/hw_pagetable.c | 28 ++++++++++++++++++++++--- > drivers/iommu/iommufd/iommufd_private.h | 5 ++++- > 3 files changed, 30 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > index 5c352807d946..19cd6df46c6a 100644 > --- a/drivers/iommu/iommufd/device.c > +++ b/drivers/iommu/iommufd/device.c > @@ -558,7 +558,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev, > } > > hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev, > - immediate_attach); > + NULL, NULL, immediate_attach); > if (IS_ERR(hwpt)) { > destroy_hwpt = ERR_CAST(hwpt); > goto out_unlock; > diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c > index 84b4a11e62f8..16e92a1c150b 100644 > --- a/drivers/iommu/iommufd/hw_pagetable.c > +++ b/drivers/iommu/iommufd/hw_pagetable.c > @@ -24,6 +24,8 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj) > if (hwpt->domain) > iommu_domain_free(hwpt->domain); > > + if (hwpt->parent) > + refcount_dec(&hwpt->parent->obj.users); > refcount_dec(&hwpt->ioas->obj.users); > } > > @@ -46,6 +48,8 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt) > * @ictx: iommufd context > * @ioas: IOAS to associate the domain with > * @idev: Device to get an iommu_domain for > + * @parent: Optional parent HWPT to associate with the domain with > + * @user_data: Optional user_data pointer > * @immediate_attach: True if idev should be attached to the hwpt > * > * Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT > @@ -54,14 +58,20 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt) > */ > struct iommufd_hw_pagetable * > iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, > - struct iommufd_device *idev, bool immediate_attach) > + struct iommufd_device *idev, > + struct iommufd_hw_pagetable *parent, > + void *user_data, bool immediate_attach) > { > const struct iommu_ops *ops = dev_iommu_ops(idev->dev); > + struct iommu_domain *parent_domain = NULL; > struct iommufd_hw_pagetable *hwpt; > int rc; > > lockdep_assert_held(&ioas->mutex); > > + if (parent && !ops->domain_alloc_user) > + return ERR_PTR(-EOPNOTSUPP);
My understanding here is that we are checking whether domain_alloc_user is required. It seems that as long as the caller inputs a valid user_data or parent, domain_alloc_user is required. If so,
if ((user_data || parent) && !ops->domain_alloc_user) return ERR_PTR(-EOPNOTSUPP);
Best regards, baolu
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