From 7a853c2d5951419fdf3c1c9d2b6f5a38f6a6857d Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:45 -0800 Subject: mm: Change CONFIG option for mm->pasid field This currently depends on CONFIG_IOMMU_SUPPORT. But it is only needed when CONFIG_IOMMU_SVA option is enabled. Change the CONFIG guards around definition and initialization of mm->pasid field. Suggested-by: Jacob Pan Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Thomas Gleixner Reviewed-by: Lu Baolu Link: https://lore.kernel.org/r/20220207230254.3342514-3-fenghua.yu@intel.com --- include/linux/mm_types.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5140e5feb486..c5cbfd7915ad 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -631,7 +631,7 @@ struct mm_struct { #endif struct work_struct async_put_work; -#ifdef CONFIG_IOMMU_SUPPORT +#ifdef CONFIG_IOMMU_SVA u32 pasid; #endif } __randomize_layout; -- cgit v1.2.3 From 7a5fbc9bcba5325a45297a4ba00091f39a63a1ed Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:46 -0800 Subject: iommu/ioasid: Introduce a helper to check for valid PASIDs Define a pasid_valid() helper to check if a given PASID is valid. [ bp: Massage commit message. ] Suggested-by: Ashok Raj Suggested-by: Jacob Pan Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Thomas Gleixner Reviewed-by: Lu Baolu Link: https://lore.kernel.org/r/20220207230254.3342514-4-fenghua.yu@intel.com --- include/linux/ioasid.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include') diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h index e9dacd4b9f6b..2237f64dbaae 100644 --- a/include/linux/ioasid.h +++ b/include/linux/ioasid.h @@ -41,6 +41,10 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, int ioasid_register_allocator(struct ioasid_allocator_ops *allocator); void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator); int ioasid_set_data(ioasid_t ioasid, void *data); +static inline bool pasid_valid(ioasid_t ioasid) +{ + return ioasid != INVALID_IOASID; +} #else /* !CONFIG_IOASID */ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, @@ -78,5 +82,10 @@ static inline int ioasid_set_data(ioasid_t ioasid, void *data) return -ENOTSUPP; } +static inline bool pasid_valid(ioasid_t ioasid) +{ + return false; +} + #endif /* CONFIG_IOASID */ #endif /* __LINUX_IOASID_H */ -- cgit v1.2.3 From a6cbd44093ef305b02ad5f80ed54abf0148a696c Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:47 -0800 Subject: kernel/fork: Initialize mm's PASID A new mm doesn't have a PASID yet when it's created. Initialize the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1). INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be allocated to a user process. Initializing the process's PASID to 0 may cause confusion that's why the process uses the reserved kernel legacy DMA PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly tells the process doesn't have a valid PASID yet. Even though the only user of mm_pasid_init() is in fork.c, define it in as the first of three mm/pasid life cycle functions (init/set/drop) to keep these all together. Suggested-by: Dave Hansen Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20220207230254.3342514-5-fenghua.yu@intel.com --- include/linux/sched/mm.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include') diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index aa5f09ca5bcf..c74d1edbac2f 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -8,6 +8,7 @@ #include #include #include +#include /* * Routines for handling mm_structs @@ -433,4 +434,13 @@ static inline void membarrier_update_current_mm(struct mm_struct *next_mm) } #endif +#ifdef CONFIG_IOMMU_SVA +static inline void mm_pasid_init(struct mm_struct *mm) +{ + mm->pasid = INVALID_IOASID; +} +#else +static inline void mm_pasid_init(struct mm_struct *mm) {} +#endif + #endif /* _LINUX_SCHED_MM_H */ -- cgit v1.2.3 From 701fac40384f07197b106136012804c3cae0b3de Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:48 -0800 Subject: iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit PASIDs are process-wide. It was attempted to use refcounted PASIDs to free them when the last thread drops the refcount. This turned out to be complex and error prone. Given the fact that the PASID space is 20 bits, which allows up to 1M processes to have a PASID associated concurrently, PASID resource exhaustion is not a realistic concern. Therefore, it was decided to simplify the approach and stick with lazy on demand PASID allocation, but drop the eager free approach and make an allocated PASID's lifetime bound to the lifetime of the process. Get rid of the refcounting mechanisms and replace/rename the interfaces to reflect this new approach. [ bp: Massage commit message. ] Suggested-by: Dave Hansen Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Lu Baolu Reviewed-by: Jacob Pan Reviewed-by: Thomas Gleixner Acked-by: Joerg Roedel Link: https://lore.kernel.org/r/20220207230254.3342514-6-fenghua.yu@intel.com --- include/linux/ioasid.h | 12 ++---------- include/linux/sched/mm.h | 16 ++++++++++++++++ 2 files changed, 18 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h index 2237f64dbaae..af1c9d62e642 100644 --- a/include/linux/ioasid.h +++ b/include/linux/ioasid.h @@ -34,8 +34,7 @@ struct ioasid_allocator_ops { #if IS_ENABLED(CONFIG_IOASID) ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, void *private); -void ioasid_get(ioasid_t ioasid); -bool ioasid_put(ioasid_t ioasid); +void ioasid_free(ioasid_t ioasid); void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool (*getter)(void *)); int ioasid_register_allocator(struct ioasid_allocator_ops *allocator); @@ -53,14 +52,7 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, return INVALID_IOASID; } -static inline void ioasid_get(ioasid_t ioasid) -{ -} - -static inline bool ioasid_put(ioasid_t ioasid) -{ - return false; -} +static inline void ioasid_free(ioasid_t ioasid) { } static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool (*getter)(void *)) diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index c74d1edbac2f..a80356e9dc69 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -439,8 +439,24 @@ static inline void mm_pasid_init(struct mm_struct *mm) { mm->pasid = INVALID_IOASID; } + +/* Associate a PASID with an mm_struct: */ +static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) +{ + mm->pasid = pasid; +} + +static inline void mm_pasid_drop(struct mm_struct *mm) +{ + if (pasid_valid(mm->pasid)) { + ioasid_free(mm->pasid); + mm->pasid = INVALID_IOASID; + } +} #else static inline void mm_pasid_init(struct mm_struct *mm) {} +static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) {} +static inline void mm_pasid_drop(struct mm_struct *mm) {} #endif #endif /* _LINUX_SCHED_MM_H */ -- cgit v1.2.3 From a3d29e8291b622780eb6e4e3eeaf2b24ec78fd43 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 7 Feb 2022 15:02:50 -0800 Subject: sched: Define and initialize a flag to identify valid PASID in the task Add a new single bit field to the task structure to track whether this task has initialized the IA32_PASID MSR to the mm's PASID. Initialize the field to zero when creating a new task with fork/clone. Signed-off-by: Peter Zijlstra Co-developed-by: Fenghua Yu Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20220207230254.3342514-8-fenghua.yu@intel.com --- include/linux/sched.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index 75ba8aa60248..4e5de3aed410 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -938,6 +938,9 @@ struct task_struct { /* Recursion prevention for eventfd_signal() */ unsigned in_eventfd_signal:1; #endif +#ifdef CONFIG_IOMMU_SVA + unsigned pasid_activated:1; +#endif unsigned long atomic_flags; /* Flags requiring atomic access. */ -- cgit v1.2.3