FAILED: patch "[PATCH] iommu/virtio: Make instance lookup robust" failed to apply to 6.16-stable tree

FAILED: patch "[PATCH] iommu/virtio: Make instance lookup robust" failed to apply to 6.16-stable tree

[gregkh]

The patch below does not apply to the 6.16-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 72b6f7cd89cea8251979b65528d302f9c0ed37bf
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082258-exert-mousy-2b51@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 72b6f7cd89cea8251979b65528d302f9c0ed37bf Mon Sep 17 00:00:00 2001
From: Robin Murphy <robin.murphy@arm.com>
Date: Thu, 14 Aug 2025 17:47:16 +0100
Subject: [PATCH] iommu/virtio: Make instance lookup robust

Much like arm-smmu in commit 7d835134d4e1 ("iommu/arm-smmu: Make
instance lookup robust"), virtio-iommu appears to have the same issue
where iommu_device_register() makes the IOMMU instance visible to other
API callers (including itself) straight away, but internally the
instance isn't ready to recognise itself for viommu_probe_device() to
work correctly until after viommu_probe() has returned. This matters a
lot more now that bus_iommu_probe() has the DT/VIOT knowledge to probe
client devices the way that was always intended. Tweak the lookup and
initialisation in much the same way as for arm-smmu, to ensure that what
we register is functional and ready to go.

Cc: stable@vger.kernel.org
Fixes: bcb81ac6ae3c ("iommu: Get DT/ACPI parsing into the proper probe path")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/308911aaa1f5be32a3a709996c7bd6cf71d30f33.1755190036.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 532db1de201b..b39d6f134ab2 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -998,8 +998,7 @@ static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
 	iommu_dma_get_resv_regions(dev, head);
 }
 
-static const struct iommu_ops viommu_ops;
-static struct virtio_driver virtio_iommu_drv;
+static const struct bus_type *virtio_bus_type;
 
 static int viommu_match_node(struct device *dev, const void *data)
 {
@@ -1008,8 +1007,9 @@ static int viommu_match_node(struct device *dev, const void *data)
 
 static struct viommu_dev *viommu_get_by_fwnode(struct fwnode_handle *fwnode)
 {
-	struct device *dev = driver_find_device(&virtio_iommu_drv.driver, NULL,
-						fwnode, viommu_match_node);
+	struct device *dev = bus_find_device(virtio_bus_type, NULL, fwnode,
+					     viommu_match_node);
+
 	put_device(dev);
 
 	return dev ? dev_to_virtio(dev)->priv : NULL;
@@ -1160,6 +1160,9 @@ static int viommu_probe(struct virtio_device *vdev)
 	if (!viommu)
 		return -ENOMEM;
 
+	/* Borrow this for easy lookups later */
+	virtio_bus_type = dev->bus;
+
 	spin_lock_init(&viommu->request_lock);
 	ida_init(&viommu->domain_ids);
 	viommu->dev = dev;
@@ -1229,10 +1232,10 @@ static int viommu_probe(struct virtio_device *vdev)
 	if (ret)
 		goto err_free_vqs;
 
-	iommu_device_register(&viommu->iommu, &viommu_ops, parent_dev);
-
 	vdev->priv = viommu;
 
+	iommu_device_register(&viommu->iommu, &viommu_ops, parent_dev);
+
 	dev_info(dev, "input address: %u bits\n",
 		 order_base_2(viommu->geometry.aperture_end));
 	dev_info(dev, "page mask: %#llx\n", viommu->pgsize_bitmap);

[PATCH 6.16.y 1/2] iommu: Remove ops.pgsize_bitmap from drivers that don't use it

[Sasha Levin]

From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit 8901812485de1356e3757958af40fe0d3a48e986 ]

These drivers all set the domain->pgsize_bitmap in their
domain_alloc_paging() functions, so the ops value is never used. Delete
it.

Reviewed-by: Sven Peter <sven@svenpeter.dev> # for Apple DART
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Tomasz Jeznach <tjeznach@rivosinc.com> # for RISC-V
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/3-v2-68a2e1ba507c+1fb-iommu_rm_ops_pgsize_jgg@nvidia.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Stable-dep-of: 72b6f7cd89ce ("iommu/virtio: Make instance lookup robust")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iommu/apple-dart.c       | 1 -
 drivers/iommu/intel/iommu.c      | 1 -
 drivers/iommu/iommufd/selftest.c | 1 -
 drivers/iommu/riscv/iommu.c      | 1 -
 drivers/iommu/virtio-iommu.c     | 6 ++----
 5 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 757d24f67ad4..190f28d76615 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -991,7 +991,6 @@ static const struct iommu_ops apple_dart_iommu_ops = {
 	.of_xlate = apple_dart_of_xlate,
 	.def_domain_type = apple_dart_def_domain_type,
 	.get_resv_regions = apple_dart_get_resv_regions,
-	.pgsize_bitmap = -1UL, /* Restricted during dart probe */
 	.owner = THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= apple_dart_attach_dev_paging,
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index ab4cd742f095..c239e280e43d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4390,7 +4390,6 @@ const struct iommu_ops intel_iommu_ops = {
 	.device_group		= intel_iommu_device_group,
 	.is_attach_deferred	= intel_iommu_is_attach_deferred,
 	.def_domain_type	= device_def_domain_type,
-	.pgsize_bitmap		= SZ_4K,
 	.page_response		= intel_iommu_page_response,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev		= intel_iommu_attach_device,
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 6bd0abf9a641..c52bf037a2f0 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -801,7 +801,6 @@ static const struct iommu_ops mock_ops = {
 	.default_domain = &mock_blocking_domain,
 	.blocked_domain = &mock_blocking_domain,
 	.owner = THIS_MODULE,
-	.pgsize_bitmap = MOCK_IO_PAGE_SIZE,
 	.hw_info = mock_domain_hw_info,
 	.domain_alloc_paging_flags = mock_domain_alloc_paging_flags,
 	.domain_alloc_nested = mock_domain_alloc_nested,
diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index bb57092ca901..2d0d31ba2886 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c
@@ -1533,7 +1533,6 @@ static void riscv_iommu_release_device(struct device *dev)
 }
 
 static const struct iommu_ops riscv_iommu_ops = {
-	.pgsize_bitmap = SZ_4K,
 	.of_xlate = riscv_iommu_of_xlate,
 	.identity_domain = &riscv_iommu_identity_domain,
 	.blocked_domain = &riscv_iommu_blocking_domain,
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index ecd41fb03e5a..532db1de201b 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -998,7 +998,7 @@ static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
 	iommu_dma_get_resv_regions(dev, head);
 }
 
-static struct iommu_ops viommu_ops;
+static const struct iommu_ops viommu_ops;
 static struct virtio_driver virtio_iommu_drv;
 
 static int viommu_match_node(struct device *dev, const void *data)
@@ -1086,7 +1086,7 @@ static bool viommu_capable(struct device *dev, enum iommu_cap cap)
 	}
 }
 
-static struct iommu_ops viommu_ops = {
+static const struct iommu_ops viommu_ops = {
 	.capable		= viommu_capable,
 	.domain_alloc_identity	= viommu_domain_alloc_identity,
 	.domain_alloc_paging	= viommu_domain_alloc_paging,
@@ -1217,8 +1217,6 @@ static int viommu_probe(struct virtio_device *vdev)
 		viommu->first_domain++;
 	}
 
-	viommu_ops.pgsize_bitmap = viommu->pgsize_bitmap;
-
 	virtio_device_ready(vdev);
 
 	/* Populate the event queue with buffers */
-- 
2.50.1

[PATCH 6.16.y 2/2] iommu/virtio: Make instance lookup robust

[Sasha Levin]

From: Robin Murphy <robin.murphy@arm.com>

[ Upstream commit 72b6f7cd89cea8251979b65528d302f9c0ed37bf ]

Much like arm-smmu in commit 7d835134d4e1 ("iommu/arm-smmu: Make
instance lookup robust"), virtio-iommu appears to have the same issue
where iommu_device_register() makes the IOMMU instance visible to other
API callers (including itself) straight away, but internally the
instance isn't ready to recognise itself for viommu_probe_device() to
work correctly until after viommu_probe() has returned. This matters a
lot more now that bus_iommu_probe() has the DT/VIOT knowledge to probe
client devices the way that was always intended. Tweak the lookup and
initialisation in much the same way as for arm-smmu, to ensure that what
we register is functional and ready to go.

Cc: stable@vger.kernel.org
Fixes: bcb81ac6ae3c ("iommu: Get DT/ACPI parsing into the proper probe path")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/308911aaa1f5be32a3a709996c7bd6cf71d30f33.1755190036.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iommu/virtio-iommu.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 532db1de201b..b39d6f134ab2 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -998,8 +998,7 @@ static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
 	iommu_dma_get_resv_regions(dev, head);
 }
 
-static const struct iommu_ops viommu_ops;
-static struct virtio_driver virtio_iommu_drv;
+static const struct bus_type *virtio_bus_type;
 
 static int viommu_match_node(struct device *dev, const void *data)
 {
@@ -1008,8 +1007,9 @@ static int viommu_match_node(struct device *dev, const void *data)
 
 static struct viommu_dev *viommu_get_by_fwnode(struct fwnode_handle *fwnode)
 {
-	struct device *dev = driver_find_device(&virtio_iommu_drv.driver, NULL,
-						fwnode, viommu_match_node);
+	struct device *dev = bus_find_device(virtio_bus_type, NULL, fwnode,
+					     viommu_match_node);
+
 	put_device(dev);
 
 	return dev ? dev_to_virtio(dev)->priv : NULL;
@@ -1160,6 +1160,9 @@ static int viommu_probe(struct virtio_device *vdev)
 	if (!viommu)
 		return -ENOMEM;
 
+	/* Borrow this for easy lookups later */
+	virtio_bus_type = dev->bus;
+
 	spin_lock_init(&viommu->request_lock);
 	ida_init(&viommu->domain_ids);
 	viommu->dev = dev;
@@ -1229,10 +1232,10 @@ static int viommu_probe(struct virtio_device *vdev)
 	if (ret)
 		goto err_free_vqs;
 
-	iommu_device_register(&viommu->iommu, &viommu_ops, parent_dev);
-
 	vdev->priv = viommu;
 
+	iommu_device_register(&viommu->iommu, &viommu_ops, parent_dev);
+
 	dev_info(dev, "input address: %u bits\n",
 		 order_base_2(viommu->geometry.aperture_end));
 	dev_info(dev, "page mask: %#llx\n", viommu->pgsize_bitmap);
-- 
2.50.1