diff mbox series

[v7,08/14] KVM: Rename mmu_notifier_*

Message ID 20220706082016.2603916-9-chao.p.peng@linux.intel.com
State New
Headers show
Series KVM: mm: fd-based approach for supporting KVM guest private memory | expand

Commit Message

Chao Peng July 6, 2022, 8:20 a.m. UTC
The sync mechanism between mmu_notifier and page fault handler employs
fields mmu_notifier_seq/count and mmu_notifier_range_start/end. For the
to be added private memory, there is the same mechanism needed but not
rely on mmu_notifier (It uses new introduced memfile_notifier). This
patch renames the existing fields and related helper functions to a
neutral name mmu_updating_* so private memory can reuse.

No functional change intended.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
 arch/arm64/kvm/mmu.c                     |  8 ++---
 arch/mips/kvm/mmu.c                      | 10 +++---
 arch/powerpc/include/asm/kvm_book3s_64.h |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_host.c    |  4 +--
 arch/powerpc/kvm/book3s_64_mmu_hv.c      |  4 +--
 arch/powerpc/kvm/book3s_64_mmu_radix.c   |  6 ++--
 arch/powerpc/kvm/book3s_hv_nested.c      |  2 +-
 arch/powerpc/kvm/book3s_hv_rm_mmu.c      |  8 ++---
 arch/powerpc/kvm/e500_mmu_host.c         |  4 +--
 arch/riscv/kvm/mmu.c                     |  4 +--
 arch/x86/kvm/mmu/mmu.c                   | 14 ++++----
 arch/x86/kvm/mmu/paging_tmpl.h           |  4 +--
 include/linux/kvm_host.h                 | 38 ++++++++++-----------
 virt/kvm/kvm_main.c                      | 42 +++++++++++-------------
 virt/kvm/pfncache.c                      | 14 ++++----
 15 files changed, 81 insertions(+), 83 deletions(-)

Comments

Sean Christopherson July 29, 2022, 7:02 p.m. UTC | #1
On Wed, Jul 06, 2022, Chao Peng wrote:
> The sync mechanism between mmu_notifier and page fault handler employs
> fields mmu_notifier_seq/count and mmu_notifier_range_start/end. For the
> to be added private memory, there is the same mechanism needed but not
> rely on mmu_notifier (It uses new introduced memfile_notifier). This
> patch renames the existing fields and related helper functions to a
> neutral name mmu_updating_* so private memory can reuse.

mmu_updating_* is too broad of a term, e.g. page faults and many other operations
also update the mmu.  Although the name most definitely came from the mmu_notifier,
it's not completely inaccurate for other sources, e.g. KVM's MMU is still being
notified of something, even if the source is not the actual mmu_notifier.

If we really want a different name, I'd vote for nomenclature that captures the
invalidation aspect, which is really what the variables are all trackng, e.g.

  mmu_invalidate_seq
  mmu_invalidate_in_progress
  mmu_invalidate_range_start
  mmu_invalidate_range_end
Chao Peng Aug. 3, 2022, 10:13 a.m. UTC | #2
On Fri, Jul 29, 2022 at 07:02:12PM +0000, Sean Christopherson wrote:
> On Wed, Jul 06, 2022, Chao Peng wrote:
> > The sync mechanism between mmu_notifier and page fault handler employs
> > fields mmu_notifier_seq/count and mmu_notifier_range_start/end. For the
> > to be added private memory, there is the same mechanism needed but not
> > rely on mmu_notifier (It uses new introduced memfile_notifier). This
> > patch renames the existing fields and related helper functions to a
> > neutral name mmu_updating_* so private memory can reuse.
> 
> mmu_updating_* is too broad of a term, e.g. page faults and many other operations
> also update the mmu.  Although the name most definitely came from the mmu_notifier,
> it's not completely inaccurate for other sources, e.g. KVM's MMU is still being
> notified of something, even if the source is not the actual mmu_notifier.
> 
> If we really want a different name, I'd vote for nomenclature that captures the
> invalidation aspect, which is really what the variables are all trackng, e.g.
> 
>   mmu_invalidate_seq
>   mmu_invalidate_in_progress
>   mmu_invalidate_range_start
>   mmu_invalidate_range_end

Looks good to me. Thanks.

Chao
Paolo Bonzini Aug. 5, 2022, 7:54 p.m. UTC | #3
On 7/29/22 21:02, Sean Christopherson wrote:
> If we really want a different name, I'd vote for nomenclature that captures the
> invalidation aspect, which is really what the variables are all trackng, e.g.
> 
>    mmu_invalidate_seq
>    mmu_invalidate_in_progress
>    mmu_invalidate_range_start
>    mmu_invalidate_range_end
> 

Agreed, and this can of course be committed separately if Chao Peng 
sends it outside this series.

Paolo
Chao Peng Aug. 10, 2022, 8:09 a.m. UTC | #4
On Fri, Aug 05, 2022 at 09:54:35PM +0200, Paolo Bonzini wrote:
> On 7/29/22 21:02, Sean Christopherson wrote:
> > If we really want a different name, I'd vote for nomenclature that captures the
> > invalidation aspect, which is really what the variables are all trackng, e.g.
> > 
> >    mmu_invalidate_seq
> >    mmu_invalidate_in_progress
> >    mmu_invalidate_range_start
> >    mmu_invalidate_range_end
> > 
> 
> Agreed, and this can of course be committed separately if Chao Peng sends it
> outside this series.

I will do that, probably also includes:
  06/14 KVM: Rename KVM_PRIVATE_MEM_SLOT

Chao
> 
> Paolo
Sean Christopherson May 24, 2023, 8:16 p.m. UTC | #5
On Wed, May 24, 2023, Kautuk Consul wrote:
> On 2023-05-23 07:19:43, Sean Christopherson wrote:
> > On Tue, May 23, 2023, Kautuk Consul wrote:
> > > On 2022-07-06 16:20:10, Chao Peng wrote:
> > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > > > index e9153b54e2a4..c262ebb168a7 100644
> > > > --- a/include/linux/kvm_host.h
> > > > +++ b/include/linux/kvm_host.h
> > > > @@ -765,10 +765,10 @@ struct kvm {
> > > >  
> > > >  #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> > > >  	struct mmu_notifier mmu_notifier;
> > > > -	unsigned long mmu_notifier_seq;
> > > > -	long mmu_notifier_count;
> > > > -	gfn_t mmu_notifier_range_start;
> > > > -	gfn_t mmu_notifier_range_end;
> > > > +	unsigned long mmu_updating_seq;
> > > > +	long mmu_updating_count;
> > > 
> > > Can we convert mmu_updating_seq and mmu_updating_count to atomic_t ?
> > 
> > Heh, can we?  Yes.  Should we?  No.
> > 
> > > I see that not all accesses to these are under the kvm->mmu_lock
> > > spinlock.
> > 
> > Ya, working as intended.  Ignoring gfn_to_pfn_cache for the moment, all accesses
> > to mmu_invalidate_in_progress (was mmu_notifier_count / mmu_updating_count above)
> > are done under mmu_lock.  And for for mmu_notifier_seq (mmu_updating_seq above),
> > all writes and some reads are done under mmu_lock.  The only reads that are done
> > outside of mmu_lock are the initial snapshots of the sequence number.
> > 
> > gfn_to_pfn_cache uses a different locking scheme, the comments in
> > mmu_notifier_retry_cache() do a good job explaining the ordering.
> > 
> > > This will also remove the need for putting separate smp_wmb() and
> > > smp_rmb() memory barriers while accessing these structure members.
> > 
> > No, the memory barriers aren't there to provide any kind of atomicity.  The barriers
> > exist to ensure that stores and loads to/from the sequence and invalidate in-progress
> > counts are ordered relative to the invalidation (stores to counts) and creation (loads)
> > of SPTEs.  Making the counts atomic changes nothing because atomic operations don't
> > guarantee the necessary ordering.
> I'm not saying that the memory barriers provide atomicity.
> My comment was based on the assumption that "all atomic operations are
> implicit memory barriers". If that assumption is true then we won't need
> the memory barriers here if we use atomic operations for protecting
> these 2 structure members.

Atomics aren't memory barriers on all architectures, e.g. see the various
definitions of smp_mb__after_atomic().

Even if atomic operations did provide barriers, using an atomic would be overkill
and a net negative.  On strongly ordered architectures like x86, memory barriers are
just compiler barriers, whereas atomics may be more expensive.  Of course, the only
accesses outside of mmu_lock are reads, so on x86 that "atomic" access is just a
READ_ONCE() load, but that's not the case for all architectures.

Anyways, the point is that atomics and memory barriers are different things that
serve different purposes.
Peter Zijlstra May 24, 2023, 8:33 p.m. UTC | #6
On Wed, May 24, 2023 at 01:16:03PM -0700, Sean Christopherson wrote:

> Atomics aren't memory barriers on all architectures, e.g. see the various
> definitions of smp_mb__after_atomic().
> 
> Even if atomic operations did provide barriers, using an atomic would be overkill
> and a net negative.  On strongly ordered architectures like x86, memory barriers are
> just compiler barriers, whereas atomics may be more expensive. 

Not quite, smp_{r,w}mb() and smp_mb__{before,after}_atomic() are
compiler barriers on the TSO archs, but smp_mb() very much isn't. TSO
still allows stores to be delayed vs later loads (iow it doesn't pretend
to hide the store buffer).

> Of course, the only
> accesses outside of mmu_lock are reads, so on x86 that "atomic" access is just a
> READ_ONCE() load, but that's not the case for all architectures.

This is true on *all* archs. atomic_set() and atomic_read() are no more
and no less than WRITE_ONCE() / READ_ONCE().

> Anyways, the point is that atomics and memory barriers are different things that
> serve different purposes.

This is true; esp. on the weakly ordered architectures where atomics do
not naturally imply any ordering.
Peter Zijlstra May 25, 2023, 8:54 a.m. UTC | #7
On Wed, May 24, 2023 at 02:39:50PM -0700, Sean Christopherson wrote:
> On Wed, May 24, 2023, Peter Zijlstra wrote:
> > On Wed, May 24, 2023 at 01:16:03PM -0700, Sean Christopherson wrote:
> > > Of course, the only accesses outside of mmu_lock are reads, so on x86 that
> > > "atomic" access is just a READ_ONCE() load, but that's not the case for all
> > > architectures.
> > 
> > This is true on *all* archs. atomic_set() and atomic_read() are no more
> > and no less than WRITE_ONCE() / READ_ONCE().
> 
> Ah, I take it s390's handcoded assembly routines are just a paranoid equivalents
> and not truly special?  "l" and "st" do sound quite generic...

Yep, compiler *should* generate the same with READ_ONCE/WRITE_ONCE.
diff mbox series

Patch

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 87f1cd0df36e..7ee6fafc24ee 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -993,7 +993,7 @@  transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
 		 * THP doesn't start to split while we are adjusting the
 		 * refcounts.
 		 *
-		 * We are sure this doesn't happen, because mmu_notifier_retry
+		 * We are sure this doesn't happen, because mmu_updating_retry
 		 * was successful and we are holding the mmu_lock, so if this
 		 * THP is trying to split, it will be blocked in the mmu
 		 * notifier before touching any of the pages, specifically
@@ -1188,9 +1188,9 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			return ret;
 	}
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
+	mmu_seq = vcpu->kvm->mmu_updating_seq;
 	/*
-	 * Ensure the read of mmu_notifier_seq happens before we call
+	 * Ensure the read of mmu_updating_seq happens before we call
 	 * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
 	 * the page we just got a reference to gets unmapped before we have a
 	 * chance to grab the mmu_lock, which ensure that if the page gets
@@ -1246,7 +1246,7 @@  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	else
 		write_lock(&kvm->mmu_lock);
 	pgt = vcpu->arch.hw_mmu->pgt;
-	if (mmu_notifier_retry(kvm, mmu_seq))
+	if (mmu_updating_retry(kvm, mmu_seq))
 		goto out_unlock;
 
 	/*
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 1bfd1b501d82..abd468c6a749 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -615,17 +615,17 @@  static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
 	 * Used to check for invalidations in progress, of the pfn that is
 	 * returned by pfn_to_pfn_prot below.
 	 */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	/*
-	 * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
+	 * Ensure the read of mmu_updating_seq isn't reordered with PTE reads in
 	 * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
 	 * risk the page we get a reference to getting unmapped before we have a
-	 * chance to grab the mmu_lock without mmu_notifier_retry() noticing.
+	 * chance to grab the mmu_lock without mmu_updating_retry () noticing.
 	 *
 	 * This smp_rmb() pairs with the effective smp_wmb() of the combination
 	 * of the pte_unmap_unlock() after the PTE is zapped, and the
 	 * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
-	 * mmu_notifier_seq is incremented.
+	 * mmu_updating_seq is incremented.
 	 */
 	smp_rmb();
 
@@ -638,7 +638,7 @@  static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
 
 	spin_lock(&kvm->mmu_lock);
 	/* Check if an invalidation has taken place since we got pfn */
-	if (mmu_notifier_retry(kvm, mmu_seq)) {
+	if (mmu_updating_retry(kvm, mmu_seq)) {
 		/*
 		 * This can happen when mappings are changed asynchronously, but
 		 * also synchronously if a COW is triggered by
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 4def2bd17b9b..4d35fb913de5 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -666,7 +666,7 @@  static inline pte_t *find_kvm_host_pte(struct kvm *kvm, unsigned long mmu_seq,
 	VM_WARN(!spin_is_locked(&kvm->mmu_lock),
 		"%s called with kvm mmu_lock not held \n", __func__);
 
-	if (mmu_notifier_retry(kvm, mmu_seq))
+	if (mmu_updating_retry(kvm, mmu_seq))
 		return NULL;
 
 	pte = __find_linux_pte(kvm->mm->pgd, ea, NULL, hshift);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index 1ae09992c9ea..78f1aae8cb60 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -90,7 +90,7 @@  int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 	unsigned long pfn;
 
 	/* used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	/* Get host physical address for gpa */
@@ -151,7 +151,7 @@  int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
 	cpte = kvmppc_mmu_hpte_cache_next(vcpu);
 
 	spin_lock(&kvm->mmu_lock);
-	if (!cpte || mmu_notifier_retry(kvm, mmu_seq)) {
+	if (!cpte || mmu_updating_retry(kvm, mmu_seq)) {
 		r = -EAGAIN;
 		goto out_unlock;
 	}
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 514fd45c1994..bcdec6a6f2a7 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -578,7 +578,7 @@  int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
 		return -EFAULT;
 
 	/* used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	ret = -EFAULT;
@@ -693,7 +693,7 @@  int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
 
 	/* Check if we might have been invalidated; let the guest retry if so */
 	ret = RESUME_GUEST;
-	if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
+	if (mmu_updating_retry(vcpu->kvm, mmu_seq)) {
 		unlock_rmap(rmap);
 		goto out_unlock;
 	}
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 42851c32ff3b..c8890ccc3f40 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -639,7 +639,7 @@  int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,
 	/* Check if we might have been invalidated; let the guest retry if so */
 	spin_lock(&kvm->mmu_lock);
 	ret = -EAGAIN;
-	if (mmu_notifier_retry(kvm, mmu_seq))
+	if (mmu_updating_retry(kvm, mmu_seq))
 		goto out_unlock;
 
 	/* Now traverse again under the lock and change the tree */
@@ -829,7 +829,7 @@  int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
 	bool large_enable;
 
 	/* used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	/*
@@ -1190,7 +1190,7 @@  void kvmppc_radix_flush_memslot(struct kvm *kvm,
 	 * Increase the mmu notifier sequence number to prevent any page
 	 * fault that read the memslot earlier from writing a PTE.
 	 */
-	kvm->mmu_notifier_seq++;
+	kvm->mmu_updating_seq++;
 	spin_unlock(&kvm->mmu_lock);
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 0644732d1a25..09f841f730da 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -1579,7 +1579,7 @@  static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu,
 	/* 2. Find the host pte for this L1 guest real address */
 
 	/* Used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	/* See if can find translation in our partition scoped tables for L1 */
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 2257fb18cb72..952b504dc98a 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -219,7 +219,7 @@  long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 	g_ptel = ptel;
 
 	/* used later to detect if we might have been invalidated */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	/* Find the memslot (if any) for this address */
@@ -366,7 +366,7 @@  long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 			rmap = real_vmalloc_addr(rmap);
 		lock_rmap(rmap);
 		/* Check for pending invalidations under the rmap chain lock */
-		if (mmu_notifier_retry(kvm, mmu_seq)) {
+		if (mmu_updating_retry(kvm, mmu_seq)) {
 			/* inval in progress, write a non-present HPTE */
 			pteh |= HPTE_V_ABSENT;
 			pteh &= ~HPTE_V_VALID;
@@ -932,7 +932,7 @@  static long kvmppc_do_h_page_init_zero(struct kvm_vcpu *vcpu,
 	int i;
 
 	/* Used later to detect if we might have been invalidated */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	arch_spin_lock(&kvm->mmu_lock.rlock.raw_lock);
@@ -960,7 +960,7 @@  static long kvmppc_do_h_page_init_copy(struct kvm_vcpu *vcpu,
 	long ret = H_SUCCESS;
 
 	/* Used later to detect if we might have been invalidated */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	arch_spin_lock(&kvm->mmu_lock.rlock.raw_lock);
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 7f16afc331ef..d7636b926f25 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -339,7 +339,7 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 	unsigned long flags;
 
 	/* used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 	smp_rmb();
 
 	/*
@@ -460,7 +460,7 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 	}
 
 	spin_lock(&kvm->mmu_lock);
-	if (mmu_notifier_retry(kvm, mmu_seq)) {
+	if (mmu_updating_retry(kvm, mmu_seq)) {
 		ret = -EAGAIN;
 		goto out;
 	}
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 081f8d2b9cf3..a7db374d3861 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -654,7 +654,7 @@  int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 		return ret;
 	}
 
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_updating_seq;
 
 	hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable);
 	if (hfn == KVM_PFN_ERR_HWPOISON) {
@@ -674,7 +674,7 @@  int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
 
 	spin_lock(&kvm->mmu_lock);
 
-	if (mmu_notifier_retry(kvm, mmu_seq))
+	if (mmu_updating_retry(kvm, mmu_seq))
 		goto out_unlock;
 
 	if (writeable) {
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0d882fad4bc1..545eb74305fe 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2908,7 +2908,7 @@  static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
 	 * If addresses are being invalidated, skip prefetching to avoid
 	 * accidentally prefetching those addresses.
 	 */
-	if (unlikely(vcpu->kvm->mmu_notifier_count))
+	if (unlikely(vcpu->kvm->mmu_updating_count))
 		return;
 
 	__direct_pte_prefetch(vcpu, sp, sptep);
@@ -2950,7 +2950,7 @@  static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 	/*
 	 * Lookup the mapping level in the current mm.  The information
 	 * may become stale soon, but it is safe to use as long as
-	 * 1) mmu_notifier_retry was checked after taking mmu_lock, and
+	 * 1) mmu_updating_retry was checked after taking mmu_lock, and
 	 * 2) mmu_lock is taken now.
 	 *
 	 * We still need to disable IRQs to prevent concurrent tear down
@@ -3035,7 +3035,7 @@  void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 		return;
 
 	/*
-	 * mmu_notifier_retry() was successful and mmu_lock is held, so
+	 * mmu_updating_retry was successful and mmu_lock is held, so
 	 * the pmd can't be split from under us.
 	 */
 	fault->goal_level = fault->req_level;
@@ -4182,7 +4182,7 @@  static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
 		return true;
 
 	return fault->slot &&
-	       mmu_notifier_retry_gfn(vcpu->kvm, mmu_seq, fault->gfn);
+	       mmu_updating_retry_gfn(vcpu->kvm, mmu_seq, fault->gfn);
 }
 
 static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
@@ -4206,7 +4206,7 @@  static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	if (r)
 		return r;
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
+	mmu_seq = vcpu->kvm->mmu_updating_seq;
 	smp_rmb();
 
 	r = kvm_faultin_pfn(vcpu, fault);
@@ -6023,7 +6023,7 @@  void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 
 	write_lock(&kvm->mmu_lock);
 
-	kvm_inc_notifier_count(kvm, gfn_start, gfn_end);
+	kvm_mmu_updating_begin(kvm, gfn_start, gfn_end);
 
 	flush = __kvm_zap_rmaps(kvm, gfn_start, gfn_end);
 
@@ -6037,7 +6037,7 @@  void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 		kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
 						   gfn_end - gfn_start);
 
-	kvm_dec_notifier_count(kvm, gfn_start, gfn_end);
+	kvm_mmu_updating_end(kvm, gfn_start, gfn_end);
 
 	write_unlock(&kvm->mmu_lock);
 }
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 2448fa8d8438..acf7e41aa02b 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -589,7 +589,7 @@  static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
 	 * If addresses are being invalidated, skip prefetching to avoid
 	 * accidentally prefetching those addresses.
 	 */
-	if (unlikely(vcpu->kvm->mmu_notifier_count))
+	if (unlikely(vcpu->kvm->mmu_updating_count))
 		return;
 
 	if (sp->role.direct)
@@ -838,7 +838,7 @@  static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	else
 		fault->max_level = walker.level;
 
-	mmu_seq = vcpu->kvm->mmu_notifier_seq;
+	mmu_seq = vcpu->kvm->mmu_updating_seq;
 	smp_rmb();
 
 	r = kvm_faultin_pfn(vcpu, fault);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e9153b54e2a4..c262ebb168a7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -765,10 +765,10 @@  struct kvm {
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
 	struct mmu_notifier mmu_notifier;
-	unsigned long mmu_notifier_seq;
-	long mmu_notifier_count;
-	gfn_t mmu_notifier_range_start;
-	gfn_t mmu_notifier_range_end;
+	unsigned long mmu_updating_seq;
+	long mmu_updating_count;
+	gfn_t mmu_updating_range_start;
+	gfn_t mmu_updating_range_end;
 #endif
 	struct list_head devices;
 	u64 manual_dirty_log_protect;
@@ -1362,8 +1362,8 @@  void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc);
 void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
 #endif
 
-void kvm_inc_notifier_count(struct kvm *kvm, gfn_t start, gfn_t end);
-void kvm_dec_notifier_count(struct kvm *kvm, gfn_t start, gfn_t end);
+void kvm_mmu_updating_begin(struct kvm *kvm, gfn_t start, gfn_t end);
+void kvm_mmu_updating_end(struct kvm *kvm, gfn_t start, gfn_t end);
 
 long kvm_arch_dev_ioctl(struct file *filp,
 			unsigned int ioctl, unsigned long arg);
@@ -1901,42 +1901,42 @@  extern const struct kvm_stats_header kvm_vcpu_stats_header;
 extern const struct _kvm_stats_desc kvm_vcpu_stats_desc[];
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
-static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
+static inline int mmu_updating_retry(struct kvm *kvm, unsigned long mmu_seq)
 {
-	if (unlikely(kvm->mmu_notifier_count))
+	if (unlikely(kvm->mmu_updating_count))
 		return 1;
 	/*
-	 * Ensure the read of mmu_notifier_count happens before the read
-	 * of mmu_notifier_seq.  This interacts with the smp_wmb() in
+	 * Ensure the read of mmu_updating_count happens before the read
+	 * of mmu_updating_seq.  This interacts with the smp_wmb() in
 	 * mmu_notifier_invalidate_range_end to make sure that the caller
-	 * either sees the old (non-zero) value of mmu_notifier_count or
-	 * the new (incremented) value of mmu_notifier_seq.
+	 * either sees the old (non-zero) value of mmu_updating_count or
+	 * the new (incremented) value of mmu_updating_seq.
 	 * PowerPC Book3s HV KVM calls this under a per-page lock
 	 * rather than under kvm->mmu_lock, for scalability, so
 	 * can't rely on kvm->mmu_lock to keep things ordered.
 	 */
 	smp_rmb();
-	if (kvm->mmu_notifier_seq != mmu_seq)
+	if (kvm->mmu_updating_seq != mmu_seq)
 		return 1;
 	return 0;
 }
 
-static inline int mmu_notifier_retry_gfn(struct kvm *kvm,
+static inline int mmu_updating_retry_gfn(struct kvm *kvm,
 					 unsigned long mmu_seq,
 					 gfn_t gfn)
 {
 	lockdep_assert_held(&kvm->mmu_lock);
 	/*
-	 * If mmu_notifier_count is non-zero, then the range maintained by
+	 * If mmu_updating_count is non-zero, then the range maintained by
 	 * kvm_mmu_notifier_invalidate_range_start contains all addresses that
 	 * might be being invalidated. Note that it may include some false
 	 * positives, due to shortcuts when handing concurrent invalidations.
 	 */
-	if (unlikely(kvm->mmu_notifier_count) &&
-	    gfn >= kvm->mmu_notifier_range_start &&
-	    gfn < kvm->mmu_notifier_range_end)
+	if (unlikely(kvm->mmu_updating_count) &&
+	    gfn >= kvm->mmu_updating_range_start &&
+	    gfn < kvm->mmu_updating_range_end)
 		return 1;
-	if (kvm->mmu_notifier_seq != mmu_seq)
+	if (kvm->mmu_updating_seq != mmu_seq)
 		return 1;
 	return 0;
 }
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4d7f0e72366f..3ae4944b9f15 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -698,30 +698,29 @@  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,
+	 * If mmu_updating_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.
 	 */
 	WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
-	if (!READ_ONCE(kvm->mmu_notifier_count))
+	if (!READ_ONCE(kvm->mmu_updating_count))
 		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_updating_begin(struct kvm *kvm, gfn_t start, gfn_t 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_updating_count++;
+	if (likely(kvm->mmu_updating_count == 1)) {
+		kvm->mmu_updating_range_start = start;
+		kvm->mmu_updating_range_end = end;
 	} else {
 		/*
 		 * Fully tracking multiple concurrent ranges has diminishing
@@ -732,10 +731,10 @@  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_updating_range_start =
+			min(kvm->mmu_updating_range_start, start);
+		kvm->mmu_updating_range_end =
+			max(kvm->mmu_updating_range_end, end);
 	}
 }
 
@@ -748,7 +747,7 @@  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_updating_begin,
 		.on_unlock	= kvm_arch_guest_memory_reclaimed,
 		.flush_on_ret	= true,
 		.may_block	= mmu_notifier_range_blockable(range),
@@ -759,7 +758,7 @@  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_updating_count
 	 * adjustments will be imbalanced.
 	 *
 	 * Pairs with the decrement in range_end().
@@ -775,7 +774,7 @@  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_updating_count.
 	 */
 	gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end,
 					  hva_range.may_block);
@@ -785,22 +784,21 @@  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_updating_end(struct kvm *kvm, gfn_t start, gfn_t 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_updating_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_updating_retry().
 	 */
-	kvm->mmu_notifier_count--;
+	kvm->mmu_updating_count--;
 }
 
 static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
@@ -812,7 +810,7 @@  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_updating_end,
 		.on_unlock	= (void *)kvm_null_fn,
 		.flush_on_ret	= false,
 		.may_block	= mmu_notifier_range_blockable(range),
@@ -833,7 +831,7 @@  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_updating_count < 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..aa6d24966a76 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -112,27 +112,27 @@  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
+	 * like mmu_updating_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.
+	 * event occurs _before_ mmu_updating_count 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_updating_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_updating_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_updating_seq is observed.
 	 */
 	smp_rmb();
-	return kvm->mmu_notifier_seq != mmu_seq;
+	return kvm->mmu_updating_seq != mmu_seq;
 }
 
 static kvm_pfn_t hva_to_pfn_retry(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
@@ -155,7 +155,7 @@  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_updating_seq;
 		smp_rmb();
 
 		write_unlock_irq(&gpc->lock);