From 35890f85573c2ebbbf3491dc66f7ee2ad63055af Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 30 Oct 2024 21:20:45 -0300 Subject: vfio: Remove VFIO_TYPE1_NESTING_IOMMU This control causes the ARM SMMU drivers to choose a stage 2 implementation for the IO pagetable (vs the stage 1 usual default), however this choice has no significant visible impact to the VFIO user. Further qemu never implemented this and no other userspace user is known. The original description in commit f5c9ecebaf2a ("vfio/iommu_type1: add new VFIO_TYPE1_NESTING_IOMMU IOMMU type") suggested this was to "provide SMMU translation services to the guest operating system" however the rest of the API to set the guest table pointer for the stage 1 and manage invalidation was never completed, or at least never upstreamed, rendering this part useless dead code. Upstream has now settled on iommufd as the uAPI for controlling nested translation. Choosing the stage 2 implementation should be done by through the IOMMU_HWPT_ALLOC_NEST_PARENT flag during domain allocation. Remove VFIO_TYPE1_NESTING_IOMMU and everything under it including the enable_nesting iommu_domain_op. Just in-case there is some userspace using this continue to treat requesting it as a NOP, but do not advertise support any more. Acked-by: Alex Williamson Reviewed-by: Mostafa Saleh Reviewed-by: Kevin Tian Reviewed-by: Jerry Snitselaar Reviewed-by: Donald Dutile Tested-by: Nicolin Chen Signed-off-by: Nicolin Chen Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/1-v4-9e99b76f3518+3a8-smmuv3_nesting_jgg@nvidia.com Signed-off-by: Will Deacon --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 16 ---------------- drivers/iommu/arm/arm-smmu/arm-smmu.c | 16 ---------------- 2 files changed, 32 deletions(-) (limited to 'drivers/iommu/arm') diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 737c5b882355..acf250aeb18b 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -3378,21 +3378,6 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) return group; } -static int arm_smmu_enable_nesting(struct iommu_domain *domain) -{ - struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); - int ret = 0; - - mutex_lock(&smmu_domain->init_mutex); - if (smmu_domain->smmu) - ret = -EPERM; - else - smmu_domain->stage = ARM_SMMU_DOMAIN_S2; - mutex_unlock(&smmu_domain->init_mutex); - - return ret; -} - static int arm_smmu_of_xlate(struct device *dev, const struct of_phandle_args *args) { @@ -3514,7 +3499,6 @@ static struct iommu_ops arm_smmu_ops = { .flush_iotlb_all = arm_smmu_flush_iotlb_all, .iotlb_sync = arm_smmu_iotlb_sync, .iova_to_phys = arm_smmu_iova_to_phys, - .enable_nesting = arm_smmu_enable_nesting, .free = arm_smmu_domain_free_paging, } }; diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 8321962b3714..12b173eec454 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1558,21 +1558,6 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) return group; } -static int arm_smmu_enable_nesting(struct iommu_domain *domain) -{ - struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); - int ret = 0; - - mutex_lock(&smmu_domain->init_mutex); - if (smmu_domain->smmu) - ret = -EPERM; - else - smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED; - mutex_unlock(&smmu_domain->init_mutex); - - return ret; -} - static int arm_smmu_set_pgtable_quirks(struct iommu_domain *domain, unsigned long quirks) { @@ -1656,7 +1641,6 @@ static struct iommu_ops arm_smmu_ops = { .flush_iotlb_all = arm_smmu_flush_iotlb_all, .iotlb_sync = arm_smmu_iotlb_sync, .iova_to_phys = arm_smmu_iova_to_phys, - .enable_nesting = arm_smmu_enable_nesting, .set_pgtable_quirks = arm_smmu_set_pgtable_quirks, .free = arm_smmu_domain_free, } -- cgit v1.2.3