| Message ID | 20220706082016.2603916-9-chao.p.peng@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: mm: fd-based approach for supporting KVM guest private memory | expand |
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
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
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
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
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 >
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. E.g. when handling a page fault, KVM snapshots the sequence outside of mmu_lock _before_ touching any state that is involved in resolving the host pfn, e.g. primary MMU state (VMAs, host page tables, etc.). After the page fault task acquires mmu_lock, KVM checks that there are no in-progress invalidations and that the sequence count is the same. This ensures that if there is a concurrent page fault and invalidation event, the page fault task will either acquire mmu_lock and create SPTEs _before_ the invalidation is processed, or the page fault task will observe either an elevated mmu_invalidate_in_progress or a different sequence count, and thus retry the page fault, if the page fault task acquires mmu_lock after the invalidation event.
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. > > E.g. when handling a page fault, KVM snapshots the sequence outside of mmu_lock > _before_ touching any state that is involved in resolving the host pfn, e.g. primary > MMU state (VMAs, host page tables, etc.). After the page fault task acquires > mmu_lock, KVM checks that there are no in-progress invalidations and that the sequence > count is the same. This ensures that if there is a concurrent page fault and > invalidation event, the page fault task will either acquire mmu_lock and create SPTEs > _before_ the invalidation is processed, or the page fault task will observe either an > elevated mmu_invalidate_in_progress or a different sequence count, and thus retry the > page fault, if the page fault task acquires mmu_lock after the invalidation event.
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.
On Wed, May 24, 2023 at 11:42:15AM +0530, Kautuk Consul wrote: > 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 It is not -- also see Documentation/atomic_t.txt. Specifically atomic_read() doesn't imply any ordering on any architecture including the strongly ordered TSO-archs (like x86).
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.
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... commit 7657e41a0bd16c9d8b3cefe8fd5d6ac3c25ae4bf Author: Heiko Carstens <hca@linux.ibm.com> Date: Thu Feb 17 13:13:58 2011 +0100 [S390] atomic: use inline asm Use inline assemblies for atomic_read/set(). This way there shouldn't be any questions or subtle volatile semantics left. static inline int __atomic_read(const atomic_t *v) { int c; asm volatile( " l %0,%1\n" : "=d" (c) : "R" (v->counter)); return c; } static inline void __atomic_set(atomic_t *v, int i) { asm volatile( " st %1,%0\n" : "=R" (v->counter) : "d" (i)); }
On 2023-05-24 22:33:36, Peter Zijlstra wrote: > 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. Thanks for the information, everyone.
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 --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);
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(-)