KVM: Rename mmu_notifier_* to mmu_invalidate_*

The motivation of this renaming is to make these variables and related
helper functions less mmu_notifier bound and can also be used for non
mmu_notifier based page invalidation. mmu_invalidate_* was chosen to
better describe the purpose of 'invalidating' a page that those
variables are used for.

  - mmu_notifier_seq/range_start/range_end are renamed to
    mmu_invalidate_seq/range_start/range_end.

  - mmu_notifier_retry{_hva} helper functions are renamed to
    mmu_invalidate_retry{_hva}.

  - mmu_notifier_count is renamed to mmu_invalidate_in_progress to
    avoid confusion with mn_active_invalidate_count.

  - While here, also update kvm_inc/dec_notifier_count() to
    kvm_mmu_invalidate_begin/end() to match the change for
    mmu_notifier_count.

No functional change intended.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Message-Id: <20220816125322.1110439-3-chao.p.peng@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 36 insertions, 33 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 44b92d773156..5142c054b03c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -702,30 +702,31 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
 
 	/*
 	 * .change_pte() must be surrounded by .invalidate_range_{start,end}().
-	 * If mmu_notifier_count is zero, then no in-progress invalidations,
-	 * including this one, found a relevant memslot at start(); rechecking
-	 * memslots here is unnecessary.  Note, a false positive (count elevated
-	 * by a different invalidation) is sub-optimal but functionally ok.
+	 * If mmu_invalidate_in_progress is zero, then no in-progress
+	 * invalidations, including this one, found a relevant memslot at
+	 * start(); rechecking memslots here is unnecessary.  Note, a false
+	 * positive (count elevated by a different invalidation) is sub-optimal
+	 * but functionally ok.
 	 */
 	WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
-	if (!READ_ONCE(kvm->mmu_notifier_count))
+	if (!READ_ONCE(kvm->mmu_invalidate_in_progress))
 		return;
 
 	kvm_handle_hva_range(mn, address, address + 1, pte, kvm_set_spte_gfn);
 }
 
-void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start,
-				   unsigned long end)
+void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start,
+			      unsigned long end)
 {
 	/*
 	 * The count increase must become visible at unlock time as no
 	 * spte can be established without taking the mmu_lock and
 	 * count is also read inside the mmu_lock critical section.
 	 */
-	kvm->mmu_notifier_count++;
-	if (likely(kvm->mmu_notifier_count == 1)) {
-		kvm->mmu_notifier_range_start = start;
-		kvm->mmu_notifier_range_end = end;
+	kvm->mmu_invalidate_in_progress++;
+	if (likely(kvm->mmu_invalidate_in_progress == 1)) {
+		kvm->mmu_invalidate_range_start = start;
+		kvm->mmu_invalidate_range_end = end;
 	} else {
 		/*
 		 * Fully tracking multiple concurrent ranges has diminishing
@@ -736,10 +737,10 @@ void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start,
 		 * accumulate and persist until all outstanding invalidates
 		 * complete.
 		 */
-		kvm->mmu_notifier_range_start =
-			min(kvm->mmu_notifier_range_start, start);
-		kvm->mmu_notifier_range_end =
-			max(kvm->mmu_notifier_range_end, end);
+		kvm->mmu_invalidate_range_start =
+			min(kvm->mmu_invalidate_range_start, start);
+		kvm->mmu_invalidate_range_end =
+			max(kvm->mmu_invalidate_range_end, end);
 	}
 }
 
@@ -752,7 +753,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 		.end		= range->end,
 		.pte		= __pte(0),
 		.handler	= kvm_unmap_gfn_range,
-		.on_lock	= kvm_inc_notifier_count,
+		.on_lock	= kvm_mmu_invalidate_begin,
 		.on_unlock	= kvm_arch_guest_memory_reclaimed,
 		.flush_on_ret	= true,
 		.may_block	= mmu_notifier_range_blockable(range),
@@ -763,7 +764,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 	/*
 	 * Prevent memslot modification between range_start() and range_end()
 	 * so that conditionally locking provides the same result in both
-	 * functions.  Without that guarantee, the mmu_notifier_count
+	 * functions.  Without that guarantee, the mmu_invalidate_in_progress
 	 * adjustments will be imbalanced.
 	 *
 	 * Pairs with the decrement in range_end().
@@ -779,7 +780,8 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 	 * any given time, and the caches themselves can check for hva overlap,
 	 * i.e. don't need to rely on memslot overlap checks for performance.
 	 * Because this runs without holding mmu_lock, the pfn caches must use
-	 * mn_active_invalidate_count (see above) instead of mmu_notifier_count.
+	 * mn_active_invalidate_count (see above) instead of
+	 * mmu_invalidate_in_progress.
 	 */
 	gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end,
 					  hva_range.may_block);
@@ -789,22 +791,22 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 	return 0;
 }
 
-void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start,
-				   unsigned long end)
+void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start,
+			    unsigned long end)
 {
 	/*
 	 * This sequence increase will notify the kvm page fault that
 	 * the page that is going to be mapped in the spte could have
 	 * been freed.
 	 */
-	kvm->mmu_notifier_seq++;
+	kvm->mmu_invalidate_seq++;
 	smp_wmb();
 	/*
 	 * The above sequence increase must be visible before the
 	 * below count decrease, which is ensured by the smp_wmb above
-	 * in conjunction with the smp_rmb in mmu_notifier_retry().
+	 * in conjunction with the smp_rmb in mmu_invalidate_retry().
 	 */
-	kvm->mmu_notifier_count--;
+	kvm->mmu_invalidate_in_progress--;
 }
 
 static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
@@ -816,7 +818,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
 		.end		= range->end,
 		.pte		= __pte(0),
 		.handler	= (void *)kvm_null_fn,
-		.on_lock	= kvm_dec_notifier_count,
+		.on_lock	= kvm_mmu_invalidate_end,
 		.on_unlock	= (void *)kvm_null_fn,
 		.flush_on_ret	= false,
 		.may_block	= mmu_notifier_range_blockable(range),
@@ -837,7 +839,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
 	if (wake)
 		rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait);
 
-	BUG_ON(kvm->mmu_notifier_count < 0);
+	BUG_ON(kvm->mmu_invalidate_in_progress < 0);
 }
 
 static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index ab519f72f2cd..68ff41d39545 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -112,27 +112,28 @@ static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_s
 {
 	/*
 	 * mn_active_invalidate_count acts for all intents and purposes
-	 * like mmu_notifier_count here; but the latter cannot be used
-	 * here because the invalidation of caches in the mmu_notifier
-	 * event occurs _before_ mmu_notifier_count is elevated.
+	 * like mmu_invalidate_in_progress here; but the latter cannot
+	 * be used here because the invalidation of caches in the
+	 * mmu_notifier event occurs _before_ mmu_invalidate_in_progress
+	 * is elevated.
 	 *
 	 * Note, it does not matter that mn_active_invalidate_count
 	 * is not protected by gpc->lock.  It is guaranteed to
 	 * be elevated before the mmu_notifier acquires gpc->lock, and
-	 * isn't dropped until after mmu_notifier_seq is updated.
+	 * isn't dropped until after mmu_invalidate_seq is updated.
 	 */
 	if (kvm->mn_active_invalidate_count)
 		return true;
 
 	/*
 	 * Ensure mn_active_invalidate_count is read before
-	 * mmu_notifier_seq.  This pairs with the smp_wmb() in
+	 * mmu_invalidate_seq.  This pairs with the smp_wmb() in
 	 * mmu_notifier_invalidate_range_end() to guarantee either the
 	 * old (non-zero) value of mn_active_invalidate_count or the
-	 * new (incremented) value of mmu_notifier_seq is observed.
+	 * new (incremented) value of mmu_invalidate_seq is observed.
 	 */
 	smp_rmb();
-	return kvm->mmu_notifier_seq != mmu_seq;
+	return kvm->mmu_invalidate_seq != mmu_seq;
 }
 
 static kvm_pfn_t hva_to_pfn_retry(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
@@ -155,7 +156,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 	gpc->valid = false;
 
 	do {
-		mmu_seq = kvm->mmu_notifier_seq;
+		mmu_seq = kvm->mmu_invalidate_seq;
 		smp_rmb();
 
 		write_unlock_irq(&gpc->lock);