Re: [PATCH v7 08/14] KVM: Rename mmu_notifier_*

Kautuk Consul
2023-05-23T07:21:53Z

On 2022-07-06 16:20:10, 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.
>
> 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(-)
>
> 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;

Can we convert mmu_updating_seq and mmu_updating_count to atomic_t ?
I see that not all accesses to these are under the kvm->mmu_lock
spinlock. This will also remove the need for putting separate smp_wmb() and
smp_rmb() memory barriers while accessing these structure members.

> + 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);
> --
> 2.25.1
>