Messages in this thread Patch in this message | | | From | Jacob Pan <> | Subject | [PATCH v12 2/8] iommu: Move global PASID allocation from SVA to core | Date | Wed, 2 Aug 2023 14:24:21 -0700 |
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Intel ENQCMD requires a single PASID to be shared between multiple devices, as the PASID is stored in a single MSR register per-process and userspace can use only that one PASID.
This means that the PASID allocation for any ENQCMD using device driver must always come from a shared global pool, regardless of what kind of domain the PASID will be used with.
Split the code for the global PASID allocator into iommu_alloc/free_global_pasid() so that drivers can attach non-SVA domains to PASIDs as well.
This patch moves global PASID allocation APIs from SVA to IOMMU APIs. Reserved PASIDs, currently only RID_PASID, are excluded from the global PASID allocation.
It is expected that device drivers will use the allocated PASIDs to attach to appropriate IOMMU domains for use.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> --- v8: fix off-by-one in max_pasid check v7: simplify range check (Baolu) v6: explicitly exclude reserved a range from SVA PASID allocation check mm PASID compatibility with device v5: move PASID range check inside API so that device drivers only pass in struct device* (Kevin) v4: move dummy functions outside ifdef CONFIG_IOMMU_SVA (Baolu) --- drivers/iommu/iommu-sva.c | 29 ++++++++++------------------- drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++ include/linux/iommu.h | 10 ++++++++++ 3 files changed, 48 insertions(+), 19 deletions(-)
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 05c0fb2acbc4..b78671a8a914 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -10,34 +10,30 @@ #include "iommu-sva.h" static DEFINE_MUTEX(iommu_sva_lock); -static DEFINE_IDA(iommu_global_pasid_ida); /* Allocate a PASID for the mm within range (inclusive) */ -static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) +static int iommu_sva_alloc_pasid(struct mm_struct *mm, struct device *dev) { + ioasid_t pasid; int ret = 0; - if (min == IOMMU_PASID_INVALID || - max == IOMMU_PASID_INVALID || - min == 0 || max < min) - return -EINVAL; - if (!arch_pgtable_dma_compat(mm)) return -EBUSY; mutex_lock(&iommu_sva_lock); /* Is a PASID already associated with this mm? */ if (mm_valid_pasid(mm)) { - if (mm->pasid < min || mm->pasid > max) + if (mm->pasid >= dev->iommu->max_pasids) ret = -EOVERFLOW; goto out; } - ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_KERNEL); - if (ret < 0) + pasid = iommu_alloc_global_pasid(dev); + if (pasid == IOMMU_PASID_INVALID) { + ret = -ENOSPC; goto out; - - mm->pasid = ret; + } + mm->pasid = pasid; ret = 0; out: mutex_unlock(&iommu_sva_lock); @@ -64,15 +60,10 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm { struct iommu_domain *domain; struct iommu_sva *handle; - ioasid_t max_pasids; int ret; - max_pasids = dev->iommu->max_pasids; - if (!max_pasids) - return ERR_PTR(-EOPNOTSUPP); - /* Allocate mm->pasid if necessary. */ - ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1); + ret = iommu_sva_alloc_pasid(mm, dev); if (ret) return ERR_PTR(ret); @@ -217,5 +208,5 @@ void mm_pasid_drop(struct mm_struct *mm) if (likely(!mm_valid_pasid(mm))) return; - ida_free(&iommu_global_pasid_ida, mm->pasid); + iommu_free_global_pasid(mm->pasid); } diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 4352a149a935..1461c845d76a 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -39,6 +39,7 @@ static struct kset *iommu_group_kset; static DEFINE_IDA(iommu_group_ida); +static DEFINE_IDA(iommu_global_pasid_ida); static unsigned int iommu_def_domain_type __read_mostly; static bool iommu_dma_strict __read_mostly = IS_ENABLED(CONFIG_IOMMU_DEFAULT_DMA_STRICT); @@ -3414,3 +3415,30 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev, return domain; } + +ioasid_t iommu_alloc_global_pasid(struct device *dev) +{ + int ret; + + /* max_pasids == 0 means that the device does not support PASID */ + if (!dev->iommu->max_pasids) + return IOMMU_PASID_INVALID; + + /* + * max_pasids is set up by vendor driver based on number of PASID bits + * supported but the IDA allocation is inclusive. + */ + ret = ida_alloc_range(&iommu_global_pasid_ida, IOMMU_FIRST_GLOBAL_PASID, + dev->iommu->max_pasids - 1, GFP_KERNEL); + return ret < 0 ? IOMMU_PASID_INVALID : ret; +} +EXPORT_SYMBOL_GPL(iommu_alloc_global_pasid); + +void iommu_free_global_pasid(ioasid_t pasid) +{ + if (WARN_ON(pasid == IOMMU_PASID_INVALID)) + return; + + ida_free(&iommu_global_pasid_ida, pasid); +} +EXPORT_SYMBOL_GPL(iommu_free_global_pasid); diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 485e4bb0347e..a745798b3f1d 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -197,6 +197,7 @@ enum iommu_dev_features { }; #define IOMMU_NO_PASID (0U) /* Reserved for DMA w/o PASID */ +#define IOMMU_FIRST_GLOBAL_PASID (1U) /*starting range for allocation */ #define IOMMU_PASID_INVALID (-1U) typedef unsigned int ioasid_t; @@ -730,6 +731,8 @@ void iommu_detach_device_pasid(struct iommu_domain *domain, struct iommu_domain * iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid, unsigned int type); +ioasid_t iommu_alloc_global_pasid(struct device *dev); +void iommu_free_global_pasid(ioasid_t pasid); #else /* CONFIG_IOMMU_API */ struct iommu_ops {}; @@ -1091,6 +1094,13 @@ iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid, { return NULL; } + +static inline ioasid_t iommu_alloc_global_pasid(struct device *dev) +{ + return IOMMU_PASID_INVALID; +} + +static inline void iommu_free_global_pasid(ioasid_t pasid) {} #endif /* CONFIG_IOMMU_API */ /** -- 2.25.1
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