Re: [PATCH v5 0/3] iommu: Clean up cookie and sw_msi in struct iommu_domain

[Nicolin Chen <nicolinc@nvidia.com>]

On Mon, Mar 24, 2025 at 09:05:14PM -0700, Nicolin Chen wrote:
> This is a clean-up series for the previous sw_msi Part-1 core series. It's
> on github:
> https://github.com/nicolinc/iommufd/commits/iommufd_msi_cleanup-v5
> 
> Changelog
> v5
>  * Add IMPORT line for IOMMUFD_INTERNAL and change IOMMUFD_DRIVER_CORE
>    to a "bool" module, fixing build module errors reported by Arnd:
>    https://lore.kernel.org/all/20250324210329.2809869-1-arnd@kernel.org/
>  * In iommu_dma_prepare_msi(), let all IDENTITY DOMAINs pass through,
>    fixing the regression with IDENTITY domains reported by Nathan:
>    https://lore.kernel.org/linux-iommu/20250324162558.GA198799@ax162/

> base-commit: da0c56520e880441d0503d0cf0d6853dcfb5f1a4

Hi Jason,

Assuming that you want to replace the commits in your for-next
tree with these patches, I rebased them on this commit:
da0c56520e88 iommu/arm-smmu-v3: Set MEV bit in nested STE for DoS mitigations

Again, sorry for the trouble.

Nicolin

P.S. Attaching git-diff against the current commit in your tree
"git diff -U1 e009e088d88e8..nicolinc/iommufd_msi_cleanup-v5":

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 0f4cc15ded1c..d96e6fabb4da 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3653,3 +3653,4 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
 	mutex_lock(&group->mutex);
-	if (group->domain) {
+	/* An IDENTITY domain must pass through */
+	if (group->domain && group->domain->type != IOMMU_DOMAIN_IDENTITY) {
 		switch (group->domain->cookie_type) {
diff --git a/drivers/iommu/iommufd/Kconfig b/drivers/iommu/iommufd/Kconfig
index 0a07f9449fd9..2beeb4f60ee5 100644
--- a/drivers/iommu/iommufd/Kconfig
+++ b/drivers/iommu/iommufd/Kconfig
@@ -2,3 +2,3 @@
 config IOMMUFD_DRIVER_CORE
-	tristate
+	bool
 	default (IOMMUFD_DRIVER || IOMMUFD) if IOMMUFD!=n
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 352513974154..a08ff0f37fc6 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -249,2 +249,3 @@ EXPORT_SYMBOL_NS_GPL(iommufd_sw_msi, "IOMMUFD");
 MODULE_DESCRIPTION("iommufd code shared with builtin modules");
+MODULE_IMPORT_NS("IOMMUFD_INTERNAL");
 MODULE_LICENSE("GPL");