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From: Nicolin Chen <nicolinc@nvidia.com>
To: <jgg@nvidia.com>, <kevin.tian@intel.com>
Cc: <robin.murphy@arm.com>, <joro@8bytes.org>, <will@kernel.org>,
	<iommu@lists.linux.dev>, <linux-kernel@vger.kernel.org>,
	<shuah@kernel.org>, <linux-kselftest@vger.kernel.org>,
	<shyamsaini@linux.microsoft.com>
Subject: [PATCH v2 1/7] iommufd/device: Move sw_msi_start from igroup to idev
Date: Tue, 14 Oct 2025 17:29:33 -0700	[thread overview]
Message-ID: <4cc8a000172572dba62f35f64f4bf0ebdba6d069.1760487869.git.nicolinc@nvidia.com> (raw)
In-Reply-To: <cover.1760487869.git.nicolinc@nvidia.com>

At the IOMMU driver layer the IOMMU_RESV_SW_MSI region is per device. So,
storing the sw_msi_start per idev makes sense.

And looking at the iommufd_sw_msi design:
 - The global ictx->sw_msi_list allocates an item for each different pair
   of sw_msi_start and msi_addr. And the allocation is per msi_desc, i.e.
   per idev.
 - Each allocated list item will be added to the igroup->required_sw_msi
   and the hwpt_paging->present_sw_msi.bitmap during a device attachment.

This makes it possible to move the sw_msi_start from struct iommufd_group
struct iommufd_device, giving a potential to support a new SET_OPTION uAPI
per idev for user space to configure the start_sw_msi for 2-stage mappings
of the MSI window.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  2 +-
 drivers/iommu/iommufd/device.c          | 31 +++++++++++++------------
 drivers/iommu/iommufd/driver.c          |  4 ++--
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 627f9b78483a0..73e5cddad24e9 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -472,7 +472,6 @@ struct iommufd_group {
 	struct iommu_group *group;
 	struct xarray pasid_attach;
 	struct iommufd_sw_msi_maps required_sw_msi;
-	phys_addr_t sw_msi_start;
 };
 
 /*
@@ -490,6 +489,7 @@ struct iommufd_device {
 	bool enforce_cache_coherency;
 	struct iommufd_vdevice *vdev;
 	bool destroying;
+	phys_addr_t sw_msi_start;
 };
 
 static inline struct iommufd_device *
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 4c842368289f0..ea7ed32bbaede 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -96,7 +96,6 @@ static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx,
 	kref_init(&new_igroup->ref);
 	mutex_init(&new_igroup->lock);
 	xa_init(&new_igroup->pasid_attach);
-	new_igroup->sw_msi_start = PHYS_ADDR_MAX;
 	/* group reference moves into new_igroup */
 	new_igroup->group = group;
 
@@ -272,6 +271,7 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
 	refcount_inc(&idev->obj.users);
 	/* igroup refcount moves into iommufd_device */
 	idev->igroup = igroup;
+	idev->sw_msi_start = PHYS_ADDR_MAX;
 
 	/*
 	 * If the caller fails after this success it must call
@@ -367,13 +367,13 @@ static unsigned int iommufd_group_device_num(struct iommufd_group *igroup,
 }
 
 #ifdef CONFIG_IRQ_MSI_IOMMU
-static int iommufd_group_setup_msi(struct iommufd_group *igroup,
-				   struct iommufd_hwpt_paging *hwpt_paging)
+static int iommufd_device_setup_msi(struct iommufd_device *idev,
+				    struct iommufd_hwpt_paging *hwpt_paging)
 {
-	struct iommufd_ctx *ictx = igroup->ictx;
+	struct iommufd_ctx *ictx = idev->ictx;
 	struct iommufd_sw_msi_map *cur;
 
-	if (igroup->sw_msi_start == PHYS_ADDR_MAX)
+	if (idev->sw_msi_start == PHYS_ADDR_MAX)
 		return 0;
 
 	/*
@@ -383,8 +383,8 @@ static int iommufd_group_setup_msi(struct iommufd_group *igroup,
 	list_for_each_entry(cur, &ictx->sw_msi_list, sw_msi_item) {
 		int rc;
 
-		if (cur->sw_msi_start != igroup->sw_msi_start ||
-		    !test_bit(cur->id, igroup->required_sw_msi.bitmap))
+		if (cur->sw_msi_start != idev->sw_msi_start ||
+		    !test_bit(cur->id, idev->igroup->required_sw_msi.bitmap))
 			continue;
 
 		rc = iommufd_sw_msi_install(ictx, hwpt_paging, cur);
@@ -395,8 +395,8 @@ static int iommufd_group_setup_msi(struct iommufd_group *igroup,
 }
 #else
 static inline int
-iommufd_group_setup_msi(struct iommufd_group *igroup,
-			struct iommufd_hwpt_paging *hwpt_paging)
+iommufd_device_setup_msi(struct iommufd_device *idev,
+			 struct iommufd_hwpt_paging *hwpt_paging)
 {
 	return 0;
 }
@@ -420,12 +420,12 @@ iommufd_device_attach_reserved_iova(struct iommufd_device *idev,
 
 	rc = iopt_table_enforce_dev_resv_regions(&hwpt_paging->ioas->iopt,
 						 idev->dev,
-						 &igroup->sw_msi_start);
+						 &idev->sw_msi_start);
 	if (rc)
 		return rc;
 
 	if (iommufd_group_first_attach(igroup, IOMMU_NO_PASID)) {
-		rc = iommufd_group_setup_msi(igroup, hwpt_paging);
+		rc = iommufd_device_setup_msi(idev, hwpt_paging);
 		if (rc) {
 			iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt,
 						  idev->dev);
@@ -745,9 +745,10 @@ iommufd_group_remove_reserved_iova(struct iommufd_group *igroup,
 }
 
 static int
-iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup,
-				       struct iommufd_hwpt_paging *hwpt_paging)
+iommufd_device_do_replace_reserved_iova(struct iommufd_device *idev,
+					struct iommufd_hwpt_paging *hwpt_paging)
 {
+	struct iommufd_group *igroup = idev->igroup;
 	struct iommufd_hwpt_paging *old_hwpt_paging;
 	struct iommufd_attach *attach;
 	struct iommufd_device *cur;
@@ -767,7 +768,7 @@ iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup,
 		}
 	}
 
-	rc = iommufd_group_setup_msi(igroup, hwpt_paging);
+	rc = iommufd_device_setup_msi(idev, hwpt_paging);
 	if (rc)
 		goto err_unresv;
 	return 0;
@@ -813,7 +814,7 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid,
 	}
 
 	if (attach_resv) {
-		rc = iommufd_group_do_replace_reserved_iova(igroup, hwpt_paging);
+		rc = iommufd_device_do_replace_reserved_iova(idev, hwpt_paging);
 		if (rc)
 			goto err_unlock;
 	}
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 6f1010da221c9..35475937d069b 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -271,7 +271,7 @@ int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
 
 	handle = to_iommufd_handle(raw_handle);
 	/* No IOMMU_RESV_SW_MSI means no change to the msi_msg */
-	if (handle->idev->igroup->sw_msi_start == PHYS_ADDR_MAX)
+	if (handle->idev->sw_msi_start == PHYS_ADDR_MAX)
 		return 0;
 
 	ictx = handle->idev->ictx;
@@ -283,7 +283,7 @@ int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
 	 */
 	msi_map = iommufd_sw_msi_get_map(handle->idev->ictx,
 					 msi_addr & PAGE_MASK,
-					 handle->idev->igroup->sw_msi_start);
+					 handle->idev->sw_msi_start);
 	if (IS_ERR(msi_map))
 		return PTR_ERR(msi_map);
 
-- 
2.43.0


  reply	other threads:[~2025-10-15  0:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-15  0:29 [PATCH v2 0/7] iommufd: Add MSI mapping support with nested SMMU (Part-2 RMR) Nicolin Chen
2025-10-15  0:29 ` Nicolin Chen [this message]
2025-10-15  0:29 ` [PATCH v2 2/7] iommufd: Pass in idev to iopt_table_enforce_dev_resv_regions Nicolin Chen
2025-10-15  0:29 ` [PATCH v2 3/7] iommufd/device: Make iommufd_device_is_attached non-static Nicolin Chen
2025-10-15  0:29 ` [PATCH v2 4/7] iommufd: Add IOMMU_OPTION_SW_MSI_START/SIZE ioctls Nicolin Chen
2025-10-15 11:58   ` kernel test robot
2025-10-15 17:20   ` Nicolin Chen
2025-10-15  0:29 ` [PATCH v2 5/7] iommufd/selftest: Add MOCK_FLAGS_DEVICE_NO_ATTACH Nicolin Chen
2025-10-15  0:29 ` [PATCH v2 6/7] iommufd/selftest: Add a testing reserved region Nicolin Chen
2025-10-15  0:29 ` [PATCH v2 7/7] iommufd/selftest: Add coverage for IOMMU_OPTION_SW_MSI_START/SIZE Nicolin Chen

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