From: Xiao Guangrong Date: Wed, 24 Feb 2016 09:51:13 +0000 (+0800) Subject: KVM: page track: add notifier support X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0eb05bf290cfe8610d9680b49abef37febd1c38a;p=linux-beck.git KVM: page track: add notifier support Notifier list is introduced so that any node wants to receive the track event can register to the list Two APIs are introduced here: - kvm_page_track_register_notifier(): register the notifier to receive track event - kvm_page_track_unregister_notifier(): stop receiving track event by unregister the notifier The callback, node->track_write() is called when a write access on the write tracked page happens Signed-off-by: Xiao Guangrong Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index e2fc5c0ec86a..eb68e6aca0cf 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -704,6 +704,7 @@ struct kvm_arch { */ struct list_head active_mmu_pages; struct list_head zapped_obsolete_pages; + struct kvm_page_track_notifier_head track_notifier_head; struct list_head assigned_dev_head; struct iommu_domain *iommu_domain; diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h index 5f16e2864e73..c2b8d24a235c 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -6,6 +6,36 @@ enum kvm_page_track_mode { KVM_PAGE_TRACK_MAX, }; +/* + * The notifier represented by @kvm_page_track_notifier_node is linked into + * the head which will be notified when guest is triggering the track event. + * + * Write access on the head is protected by kvm->mmu_lock, read access + * is protected by track_srcu. + */ +struct kvm_page_track_notifier_head { + struct srcu_struct track_srcu; + struct hlist_head track_notifier_list; +}; + +struct kvm_page_track_notifier_node { + struct hlist_node node; + + /* + * It is called when guest is writing the write-tracked page + * and write emulation is finished at that time. + * + * @vcpu: the vcpu where the write access happened. + * @gpa: the physical address written by guest. + * @new: the data was written to the address. + * @bytes: the written length. + */ + void (*track_write)(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, + int bytes); +}; + +void kvm_page_track_init(struct kvm *kvm); + void kvm_page_track_free_memslot(struct kvm_memory_slot *free, struct kvm_memory_slot *dont); int kvm_page_track_create_memslot(struct kvm_memory_slot *slot, @@ -19,4 +49,13 @@ void kvm_slot_page_track_remove_page(struct kvm *kvm, enum kvm_page_track_mode mode); bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn, enum kvm_page_track_mode mode); + +void +kvm_page_track_register_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n); +void +kvm_page_track_unregister_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n); +void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, + int bytes); #endif diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c index f127f6d04fa1..11f76436f74f 100644 --- a/arch/x86/kvm/page_track.c +++ b/arch/x86/kvm/page_track.c @@ -150,3 +150,73 @@ bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn, return !!ACCESS_ONCE(slot->arch.gfn_track[mode][index]); } + +void kvm_page_track_init(struct kvm *kvm) +{ + struct kvm_page_track_notifier_head *head; + + head = &kvm->arch.track_notifier_head; + init_srcu_struct(&head->track_srcu); + INIT_HLIST_HEAD(&head->track_notifier_list); +} + +/* + * register the notifier so that event interception for the tracked guest + * pages can be received. + */ +void +kvm_page_track_register_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n) +{ + struct kvm_page_track_notifier_head *head; + + head = &kvm->arch.track_notifier_head; + + spin_lock(&kvm->mmu_lock); + hlist_add_head_rcu(&n->node, &head->track_notifier_list); + spin_unlock(&kvm->mmu_lock); +} + +/* + * stop receiving the event interception. It is the opposed operation of + * kvm_page_track_register_notifier(). + */ +void +kvm_page_track_unregister_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n) +{ + struct kvm_page_track_notifier_head *head; + + head = &kvm->arch.track_notifier_head; + + spin_lock(&kvm->mmu_lock); + hlist_del_rcu(&n->node); + spin_unlock(&kvm->mmu_lock); + synchronize_srcu(&head->track_srcu); +} + +/* + * Notify the node that write access is intercepted and write emulation is + * finished at this time. + * + * The node should figure out if the written page is the one that node is + * interested in by itself. + */ +void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, + int bytes) +{ + struct kvm_page_track_notifier_head *head; + struct kvm_page_track_notifier_node *n; + int idx; + + head = &vcpu->kvm->arch.track_notifier_head; + + if (hlist_empty(&head->track_notifier_list)) + return; + + idx = srcu_read_lock(&head->track_srcu); + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) + if (n->track_write) + n->track_write(vcpu, gpa, new, bytes); + srcu_read_unlock(&head->track_srcu, idx); +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7b4cfea09deb..b81c14ef1e1d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4346,6 +4346,7 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, if (ret < 0) return 0; kvm_mmu_pte_write(vcpu, gpa, val, bytes); + kvm_page_track_write(vcpu, gpa, val, bytes); return 1; } @@ -4604,6 +4605,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT); kvm_mmu_pte_write(vcpu, gpa, new, bytes); + kvm_page_track_write(vcpu, gpa, new, bytes); return X86EMUL_CONTINUE; @@ -7724,6 +7726,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn); INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn); + kvm_page_track_init(kvm); + return 0; }