diff options
| -rw-r--r-- | Documentation/vm/hmm.rst | 20 | ||||
| -rw-r--r-- | include/linux/mmu_notifier.h | 38 | ||||
| -rw-r--r-- | mm/mmu_notifier.c | 136 |
3 files changed, 104 insertions, 90 deletions
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst index 893a8ba0e9fe..95fec5968362 100644 --- a/Documentation/vm/hmm.rst +++ b/Documentation/vm/hmm.rst @@ -149,14 +149,14 @@ CPU page table into a device page table; HMM helps keep both synchronized. A device driver that wants to mirror a process address space must start with the registration of a mmu_interval_notifier:: - mni->ops = &driver_ops; - int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, - unsigned long start, unsigned long length, - struct mm_struct *mm); + int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub, + struct mm_struct *mm, unsigned long start, + unsigned long length, + const struct mmu_interval_notifier_ops *ops); -During the driver_ops->invalidate() callback the device driver must perform -the update action to the range (mark range read only, or fully unmap, -etc.). The device must complete the update before the driver callback returns. +During the ops->invalidate() callback the device driver must perform the +update action to the range (mark range read only, or fully unmap, etc.). The +device must complete the update before the driver callback returns. When the device driver wants to populate a range of virtual addresses, it can use:: @@ -183,7 +183,7 @@ The usage pattern is:: struct hmm_range range; ... - range.notifier = &mni; + range.notifier = &interval_sub; range.start = ...; range.end = ...; range.pfns = ...; @@ -191,11 +191,11 @@ The usage pattern is:: range.values = ...; range.pfn_shift = ...; - if (!mmget_not_zero(mni->notifier.mm)) + if (!mmget_not_zero(interval_sub->notifier.mm)) return -EFAULT; again: - range.notifier_seq = mmu_interval_read_begin(&mni); + range.notifier_seq = mmu_interval_read_begin(&interval_sub); down_read(&mm->mmap_sem); ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT); if (ret) { diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 4342fa75dc24..736f6918335e 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -237,7 +237,7 @@ struct mmu_notifier { * was required but mmu_notifier_range_blockable(range) is false. */ struct mmu_interval_notifier_ops { - bool (*invalidate)(struct mmu_interval_notifier *mni, + bool (*invalidate)(struct mmu_interval_notifier *interval_sub, const struct mmu_notifier_range *range, unsigned long cur_seq); }; @@ -292,20 +292,21 @@ extern int __mmu_notifier_register(struct mmu_notifier *subscription, extern void mmu_notifier_unregister(struct mmu_notifier *subscription, struct mm_struct *mm); -unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni); -int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, +unsigned long +mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub); +int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub, struct mm_struct *mm, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops); int mmu_interval_notifier_insert_locked( - struct mmu_interval_notifier *mni, struct mm_struct *mm, + struct mmu_interval_notifier *interval_sub, struct mm_struct *mm, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops); -void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni); +void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub); /** * mmu_interval_set_seq - Save the invalidation sequence - * @mni - The mni passed to invalidate + * @interval_sub - The subscription passed to invalidate * @cur_seq - The cur_seq passed to the invalidate() callback * * This must be called unconditionally from the invalidate callback of a @@ -316,15 +317,16 @@ void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni); * If the caller does not call mmu_interval_read_begin() or * mmu_interval_read_retry() then this call is not required. */ -static inline void mmu_interval_set_seq(struct mmu_interval_notifier *mni, - unsigned long cur_seq) +static inline void +mmu_interval_set_seq(struct mmu_interval_notifier *interval_sub, + unsigned long cur_seq) { - WRITE_ONCE(mni->invalidate_seq, cur_seq); + WRITE_ONCE(interval_sub->invalidate_seq, cur_seq); } /** * mmu_interval_read_retry - End a read side critical section against a VA range - * mni: The range + * interval_sub: The subscription * seq: The return of the paired mmu_interval_read_begin() * * This MUST be called under a user provided lock that is also held @@ -336,15 +338,16 @@ static inline void mmu_interval_set_seq(struct mmu_interval_notifier *mni, * Returns true if an invalidation collided with this critical section, and * the caller should retry. */ -static inline bool mmu_interval_read_retry(struct mmu_interval_notifier *mni, - unsigned long seq) +static inline bool +mmu_interval_read_retry(struct mmu_interval_notifier *interval_sub, + unsigned long seq) { - return mni->invalidate_seq != seq; + return interval_sub->invalidate_seq != seq; } /** * mmu_interval_check_retry - Test if a collision has occurred - * mni: The range + * interval_sub: The subscription * seq: The return of the matching mmu_interval_read_begin() * * This can be used in the critical section between mmu_interval_read_begin() @@ -359,11 +362,12 @@ static inline bool mmu_interval_read_retry(struct mmu_interval_notifier *mni, * This call can be used as part of loops and other expensive operations to * expedite a retry. */ -static inline bool mmu_interval_check_retry(struct mmu_interval_notifier *mni, - unsigned long seq) +static inline bool +mmu_interval_check_retry(struct mmu_interval_notifier *interval_sub, + unsigned long seq) { /* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */ - return READ_ONCE(mni->invalidate_seq) != seq; + return READ_ONCE(interval_sub->invalidate_seq) != seq; } extern void __mmu_notifier_subscriptions_destroy(struct mm_struct *mm); diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 12b35d8b444a..ef3973a5d34a 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -81,7 +81,7 @@ struct mmu_notifier_subscriptions { * seq & 1 # True if a writer exists * * The later state avoids some expensive work on inv_end in the common case of - * no mni monitoring the VA. + * no mmu_interval_notifier monitoring the VA. */ static bool mn_itree_is_invalidating(struct mmu_notifier_subscriptions *subscriptions) @@ -114,13 +114,13 @@ mn_itree_inv_start_range(struct mmu_notifier_subscriptions *subscriptions, } static struct mmu_interval_notifier * -mn_itree_inv_next(struct mmu_interval_notifier *mni, +mn_itree_inv_next(struct mmu_interval_notifier *interval_sub, const struct mmu_notifier_range *range) { struct interval_tree_node *node; - node = interval_tree_iter_next(&mni->interval_tree, range->start, - range->end - 1); + node = interval_tree_iter_next(&interval_sub->interval_tree, + range->start, range->end - 1); if (!node) return NULL; return container_of(node, struct mmu_interval_notifier, interval_tree); @@ -128,7 +128,7 @@ mn_itree_inv_next(struct mmu_interval_notifier *mni, static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions) { - struct mmu_interval_notifier *mni; + struct mmu_interval_notifier *interval_sub; struct hlist_node *next; spin_lock(&subscriptions->lock); @@ -147,15 +147,16 @@ static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions) * they are progressed. This arrangement for tree updates is used to * avoid using a blocking lock during invalidate_range_start. */ - hlist_for_each_entry_safe(mni, next, &subscriptions->deferred_list, + hlist_for_each_entry_safe(interval_sub, next, + &subscriptions->deferred_list, deferred_item) { - if (RB_EMPTY_NODE(&mni->interval_tree.rb)) - interval_tree_insert(&mni->interval_tree, + if (RB_EMPTY_NODE(&interval_sub->interval_tree.rb)) + interval_tree_insert(&interval_sub->interval_tree, &subscriptions->itree); else - interval_tree_remove(&mni->interval_tree, + interval_tree_remove(&interval_sub->interval_tree, &subscriptions->itree); - hlist_del(&mni->deferred_item); + hlist_del(&interval_sub->deferred_item); } spin_unlock(&subscriptions->lock); @@ -165,12 +166,12 @@ static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions) /** * mmu_interval_read_begin - Begin a read side critical section against a VA * range - * mni: The range to use + * interval_sub: The interval subscription * * mmu_iterval_read_begin()/mmu_iterval_read_retry() implement a - * collision-retry scheme similar to seqcount for the VA range under mni. If - * the mm invokes invalidation during the critical section then - * mmu_interval_read_retry() will return true. + * collision-retry scheme similar to seqcount for the VA range under + * subscription. If the mm invokes invalidation during the critical section + * then mmu_interval_read_retry() will return true. * * This is useful to obtain shadow PTEs where teardown or setup of the SPTEs * require a blocking context. The critical region formed by this can sleep, @@ -181,25 +182,26 @@ static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions) * * The return value should be passed to mmu_interval_read_retry(). */ -unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni) +unsigned long +mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub) { struct mmu_notifier_subscriptions *subscriptions = - mni->mm->notifier_subscriptions; + interval_sub->mm->notifier_subscriptions; unsigned long seq; bool is_invalidating; /* - * If the mni has a different seq value under the user_lock than we - * started with then it has collided. + * If the subscription has a different seq value under the user_lock + * than we started with then it has collided. * - * If the mni currently has the same seq value as the subscriptions - * seq, then it is currently between invalidate_start/end and is - * colliding. + * If the subscription currently has the same seq value as the + * subscriptions seq, then it is currently between + * invalidate_start/end and is colliding. * * The locking looks broadly like this: * mn_tree_invalidate_start(): mmu_interval_read_begin(): * spin_lock - * seq = READ_ONCE(mni->invalidate_seq); + * seq = READ_ONCE(interval_sub->invalidate_seq); * seq == subs->invalidate_seq * spin_unlock * spin_lock @@ -208,7 +210,7 @@ unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni) * op->invalidate_range(): * user_lock * mmu_interval_set_seq() - * mni->invalidate_seq = seq + * interval_sub->invalidate_seq = seq * user_unlock * * [Required: mmu_interval_read_retry() == true] @@ -220,7 +222,7 @@ unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni) * * user_lock * mmu_interval_read_retry(): - * mni->invalidate_seq != seq + * interval_sub->invalidate_seq != seq * user_unlock * * Barriers are not needed here as any races here are closed by an @@ -229,12 +231,12 @@ unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni) */ spin_lock(&subscriptions->lock); /* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */ - seq = READ_ONCE(mni->invalidate_seq); + seq = READ_ONCE(interval_sub->invalidate_seq); is_invalidating = seq == subscriptions->invalidate_seq; spin_unlock(&subscriptions->lock); /* - * mni->invalidate_seq must always be set to an odd value via + * interval_sub->invalidate_seq must always be set to an odd value via * mmu_interval_set_seq() using the provided cur_seq from * mn_itree_inv_start_range(). This ensures that if seq does wrap we * will always clear the below sleep in some reasonable time as @@ -266,13 +268,16 @@ static void mn_itree_release(struct mmu_notifier_subscriptions *subscriptions, .start = 0, .end = ULONG_MAX, }; - struct mmu_interval_notifier *mni; + struct mmu_interval_notifier *interval_sub; unsigned long cur_seq; bool ret; - for (mni = mn_itree_inv_start_range(subscriptions, &range, &cur_seq); - mni; mni = mn_itree_inv_next(mni, &range)) { - ret = mni->ops->invalidate(mni, &range, cur_seq); + for (interval_sub = + mn_itree_inv_start_range(subscriptions, &range, &cur_seq); + interval_sub; + interval_sub = mn_itree_inv_next(interval_sub, &range)) { + ret = interval_sub->ops->invalidate(interval_sub, &range, + cur_seq); WARN_ON(!ret); } @@ -434,14 +439,17 @@ void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, static int mn_itree_invalidate(struct mmu_notifier_subscriptions *subscriptions, const struct mmu_notifier_range *range) { - struct mmu_interval_notifier *mni; + struct mmu_interval_notifier *interval_sub; unsigned long cur_seq; - for (mni = mn_itree_inv_start_range(subscriptions, range, &cur_seq); - mni; mni = mn_itree_inv_next(mni, range)) { + for (interval_sub = + mn_itree_inv_start_range(subscriptions, range, &cur_seq); + interval_sub; + interval_sub = mn_itree_inv_next(interval_sub, range)) { bool ret; - ret = mni->ops->invalidate(mni, range, cur_seq); + ret = interval_sub->ops->invalidate(interval_sub, range, + cur_seq); if (!ret) { if (WARN_ON(mmu_notifier_range_blockable(range))) continue; @@ -878,20 +886,21 @@ out_unlock: EXPORT_SYMBOL_GPL(mmu_notifier_put); static int __mmu_interval_notifier_insert( - struct mmu_interval_notifier *mni, struct mm_struct *mm, + struct mmu_interval_notifier *interval_sub, struct mm_struct *mm, struct mmu_notifier_subscriptions *subscriptions, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops) { - mni->mm = mm; - mni->ops = ops; - RB_CLEAR_NODE(&mni->interval_tree.rb); - mni->interval_tree.start = start; + interval_sub->mm = mm; + interval_sub->ops = ops; + RB_CLEAR_NODE(&interval_sub->interval_tree.rb); + interval_sub->interval_tree.start = start; /* * Note that the representation of the intervals in the interval tree * considers the ending point as contained in the interval. */ if (length == 0 || - check_add_overflow(start, length - 1, &mni->interval_tree.last)) + check_add_overflow(start, length - 1, + &interval_sub->interval_tree.last)) return -EOVERFLOW; /* Must call with a mmget() held */ @@ -911,30 +920,31 @@ static int __mmu_interval_notifier_insert( * possibility for live lock, instead defer the add to * mn_itree_inv_end() so this algorithm is deterministic. * - * In all cases the value for the mni->invalidate_seq should be + * In all cases the value for the interval_sub->invalidate_seq should be * odd, see mmu_interval_read_begin() */ spin_lock(&subscriptions->lock); if (subscriptions->active_invalidate_ranges) { if (mn_itree_is_invalidating(subscriptions)) - hlist_add_head(&mni->deferred_item, + hlist_add_head(&interval_sub->deferred_item, &subscriptions->deferred_list); else { subscriptions->invalidate_seq |= 1; - interval_tree_insert(&mni->interval_tree, + interval_tree_insert(&interval_sub->interval_tree, &subscriptions->itree); } - mni->invalidate_seq = subscriptions->invalidate_seq; + interval_sub->invalidate_seq = subscriptions->invalidate_seq; } else { WARN_ON(mn_itree_is_invalidating(subscriptions)); /* - * The starting seq for a mni not under invalidation should be - * odd, not equal to the current invalidate_seq and + * The starting seq for a subscription not under invalidation + * should be odd, not equal to the current invalidate_seq and * invalidate_seq should not 'wrap' to the new seq any time * soon. */ - mni->invalidate_seq = subscriptions->invalidate_seq - 1; - interval_tree_insert(&mni->interval_tree, + interval_sub->invalidate_seq = + subscriptions->invalidate_seq - 1; + interval_tree_insert(&interval_sub->interval_tree, &subscriptions->itree); } spin_unlock(&subscriptions->lock); @@ -943,7 +953,7 @@ static int __mmu_interval_notifier_insert( /** * mmu_interval_notifier_insert - Insert an interval notifier - * @mni: Interval notifier to register + * @interval_sub: Interval subscription to register * @start: Starting virtual address to monitor * @length: Length of the range to monitor * @mm : mm_struct to attach to @@ -956,7 +966,7 @@ static int __mmu_interval_notifier_insert( * The caller must use the normal interval notifier read flow via * mmu_interval_read_begin() to establish SPTEs for this range. */ -int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, +int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub, struct mm_struct *mm, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops) @@ -973,13 +983,13 @@ int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, return ret; subscriptions = mm->notifier_subscriptions; } - return __mmu_interval_notifier_insert(mni, mm, subscriptions, start, - length, ops); + return __mmu_interval_notifier_insert(interval_sub, mm, subscriptions, + start, length, ops); } EXPORT_SYMBOL_GPL(mmu_interval_notifier_insert); int mmu_interval_notifier_insert_locked( - struct mmu_interval_notifier *mni, struct mm_struct *mm, + struct mmu_interval_notifier *interval_sub, struct mm_struct *mm, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops) { @@ -995,14 +1005,14 @@ int mmu_interval_notifier_insert_locked( return ret; subscriptions = mm->notifier_subscriptions; } - return __mmu_interval_notifier_insert(mni, mm, subscriptions, start, - length, ops); + return __mmu_interval_notifier_insert(interval_sub, mm, subscriptions, + start, length, ops); } EXPORT_SYMBOL_GPL(mmu_interval_notifier_insert_locked); /** * mmu_interval_notifier_remove - Remove a interval notifier - * @mni: Interval notifier to unregister + * @interval_sub: Interval subscription to unregister * * This function must be paired with mmu_interval_notifier_insert(). It cannot * be called from any ops callback. @@ -1010,9 +1020,9 @@ EXPORT_SYMBOL_GPL(mmu_interval_notifier_insert_locked); * Once this returns ops callbacks are no longer running on other CPUs and * will not be called in future. */ -void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni) +void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub) { - struct mm_struct *mm = mni->mm; + struct mm_struct *mm = interval_sub->mm; struct mmu_notifier_subscriptions *subscriptions = mm->notifier_subscriptions; unsigned long seq = 0; @@ -1025,16 +1035,16 @@ void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni) * remove is being called after insert put this on the * deferred list, but before the deferred list was processed. */ - if (RB_EMPTY_NODE(&mni->interval_tree.rb)) { - hlist_del(&mni->deferred_item); + if (RB_EMPTY_NODE(&interval_sub->interval_tree.rb)) { + hlist_del(&interval_sub->deferred_item); } else { - hlist_add_head(&mni->deferred_item, + hlist_add_head(&interval_sub->deferred_item, &subscriptions->deferred_list); seq = subscriptions->invalidate_seq; } } else { - WARN_ON(RB_EMPTY_NODE(&mni->interval_tree.rb)); - interval_tree_remove(&mni->interval_tree, + WARN_ON(RB_EMPTY_NODE(&interval_sub->interval_tree.rb)); + interval_tree_remove(&interval_sub->interval_tree, &subscriptions->itree); } spin_unlock(&subscriptions->lock); |