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Date:   Tue, 24 Oct 2023 14:30:09 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Yi Liu <yi.l.liu@intel.com>
Cc:     joro@8bytes.org, alex.williamson@redhat.com, kevin.tian@intel.com,
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        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        zhenzhong.duan@intel.com, joao.m.martins@oracle.com
Subject: Re: [PATCH v6 07/10] iommufd: Add a nested HW pagetable object
Message-ID: <20231024173009.GQ3952@nvidia.com>
References: <20231024150609.46884-1-yi.l.liu@intel.com>
 <20231024150609.46884-8-yi.l.liu@intel.com>
 <20231024171810.GO3952@nvidia.com>
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On Tue, Oct 24, 2023 at 02:18:10PM -0300, Jason Gunthorpe wrote:
> On Tue, Oct 24, 2023 at 08:06:06AM -0700, Yi Liu wrote:
> > @@ -195,6 +279,10 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
> >  	if (pt_obj->type == IOMMUFD_OBJ_IOAS) {
> >  		struct iommufd_hwpt_paging *hwpt_paging;
> >  
> > +		if (cmd->data_type != IOMMU_HWPT_DATA_NONE) {
> > +			rc = -EINVAL;
> > +			goto out_put_pt;
> > +		}
> >  		ioas = container_of(pt_obj, struct iommufd_ioas, obj);
> >  		mutex_lock(&ioas->mutex);
> >  		hwpt_paging = iommufd_hwpt_paging_alloc(ucmd->ictx, ioas, idev,
> 
> ?? What is this?
> 
> Ah something went wrong earlier in "iommu: Pass in parent domain with
> user_data to domain_alloc_user op"

Bah, I got confused because that had half the uapi, so in this pathc
 
> Once we added the user_data we should flow it through to the op
> always.

Like this:

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 92859b907bb93c..a3382811af8a81 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -586,8 +586,8 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
 		goto out_unlock;
 	}
 
-	hwpt_paging = iommufd_hwpt_paging_alloc(idev->ictx, ioas, idev,
-						 0, immediate_attach);
+	hwpt_paging = iommufd_hwpt_paging_alloc(idev->ictx, ioas, idev, 0,
+						immediate_attach, NULL);
 	if (IS_ERR(hwpt_paging)) {
 		destroy_hwpt = ERR_CAST(hwpt_paging);
 		goto out_unlock;
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index cfd85df693d7b2..324a6d73f032ee 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -96,7 +96,8 @@ iommufd_hwpt_paging_enforce_cc(struct iommufd_hwpt_paging *hwpt_paging)
 struct iommufd_hwpt_paging *
 iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 			  struct iommufd_device *idev, u32 flags,
-			  bool immediate_attach)
+			  bool immediate_attach,
+			  const struct iommu_user_data *user_data)
 {
 	const u32 valid_flags = IOMMU_HWPT_ALLOC_NEST_PARENT |
 				IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
@@ -107,7 +108,7 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 
 	lockdep_assert_held(&ioas->mutex);
 
-	if (flags && !ops->domain_alloc_user)
+	if ((flags || user_data) && !ops->domain_alloc_user)
 		return ERR_PTR(-EOPNOTSUPP);
 	if (flags & ~valid_flags)
 		return ERR_PTR(-EOPNOTSUPP);
@@ -127,7 +128,7 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 
 	if (ops->domain_alloc_user) {
 		hwpt->domain = ops->domain_alloc_user(idev->dev, flags,
-						      NULL, NULL);
+						      NULL, user_data);
 		if (IS_ERR(hwpt->domain)) {
 			rc = PTR_ERR(hwpt->domain);
 			hwpt->domain = NULL;
@@ -210,8 +211,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	struct iommufd_hw_pagetable *hwpt;
 	int rc;
 
-	if (flags || user_data->type == IOMMU_HWPT_DATA_NONE ||
-	    !ops->domain_alloc_user)
+	if (flags || !user_data->len || !ops->domain_alloc_user)
 		return ERR_PTR(-EOPNOTSUPP);
 	if (parent->auto_domain || !parent->nest_parent)
 		return ERR_PTR(-EINVAL);
@@ -249,6 +249,11 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 {
 	struct iommu_hwpt_alloc *cmd = ucmd->cmd;
+	const struct iommu_user_data user_data = {
+		.type = cmd->data_type,
+		.uptr = u64_to_user_ptr(cmd->data_uptr),
+		.len = cmd->data_len,
+	};
 	struct iommufd_hw_pagetable *hwpt;
 	struct iommufd_ioas *ioas = NULL;
 	struct iommufd_object *pt_obj;
@@ -273,25 +278,17 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 	if (pt_obj->type == IOMMUFD_OBJ_IOAS) {
 		struct iommufd_hwpt_paging *hwpt_paging;
 
-		if (cmd->data_type != IOMMU_HWPT_DATA_NONE) {
-			rc = -EINVAL;
-			goto out_put_pt;
-		}
 		ioas = container_of(pt_obj, struct iommufd_ioas, obj);
 		mutex_lock(&ioas->mutex);
-		hwpt_paging = iommufd_hwpt_paging_alloc(ucmd->ictx, ioas, idev,
-							cmd->flags, false);
+		hwpt_paging = iommufd_hwpt_paging_alloc(
+			ucmd->ictx, ioas, idev, cmd->flags, false,
+			user_data.len ? &user_data : NULL);
 		if (IS_ERR(hwpt_paging)) {
 			rc = PTR_ERR(hwpt_paging);
 			goto out_unlock;
 		}
 		hwpt = &hwpt_paging->common;
 	} else if (pt_obj->type == IOMMUFD_OBJ_HWPT_PAGING) {
-		const struct iommu_user_data user_data = {
-			.type = cmd->data_type,
-			.uptr = u64_to_user_ptr(cmd->data_uptr),
-			.len = cmd->data_len,
-		};
 		struct iommufd_hwpt_nested *hwpt_nested;
 		struct iommufd_hwpt_paging *parent;
 
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 6fdad56893af4d..24e5a36fc875e0 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -290,7 +290,8 @@ int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd);
 struct iommufd_hwpt_paging *
 iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 			  struct iommufd_device *idev, u32 flags,
-			  bool immediate_attach);
+			  bool immediate_attach,
+			  const struct iommu_user_data *user_data);
 int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
 				struct iommufd_device *idev);
 struct iommufd_hw_pagetable *