1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_KVM_PAGE_TRACK_H
3 #define _ASM_X86_KVM_PAGE_TRACK_H
4 
5 #include <linux/kvm_types.h>
6 
7 enum kvm_page_track_mode {
8 	KVM_PAGE_TRACK_WRITE,
9 	KVM_PAGE_TRACK_MAX,
10 };
11 
12 void kvm_slot_page_track_add_page(struct kvm *kvm,
13 				  struct kvm_memory_slot *slot, gfn_t gfn,
14 				  enum kvm_page_track_mode mode);
15 void kvm_slot_page_track_remove_page(struct kvm *kvm,
16 				     struct kvm_memory_slot *slot, gfn_t gfn,
17 				     enum kvm_page_track_mode mode);
18 
19 #ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
20 /*
21  * The notifier represented by @kvm_page_track_notifier_node is linked into
22  * the head which will be notified when guest is triggering the track event.
23  *
24  * Write access on the head is protected by kvm->mmu_lock, read access
25  * is protected by track_srcu.
26  */
27 struct kvm_page_track_notifier_head {
28 	struct srcu_struct track_srcu;
29 	struct hlist_head track_notifier_list;
30 };
31 
32 struct kvm_page_track_notifier_node {
33 	struct hlist_node node;
34 
35 	/*
36 	 * It is called when guest is writing the write-tracked page
37 	 * and write emulation is finished at that time.
38 	 *
39 	 * @gpa: the physical address written by guest.
40 	 * @new: the data was written to the address.
41 	 * @bytes: the written length.
42 	 * @node: this node
43 	 */
44 	void (*track_write)(gpa_t gpa, const u8 *new, int bytes,
45 			    struct kvm_page_track_notifier_node *node);
46 
47 	/*
48 	 * Invoked when a memory region is removed from the guest.  Or in KVM
49 	 * terms, when a memslot is deleted.
50 	 *
51 	 * @gfn:       base gfn of the region being removed
52 	 * @nr_pages:  number of pages in the to-be-removed region
53 	 * @node:      this node
54 	 */
55 	void (*track_remove_region)(gfn_t gfn, unsigned long nr_pages,
56 				    struct kvm_page_track_notifier_node *node);
57 };
58 
59 void
60 kvm_page_track_register_notifier(struct kvm *kvm,
61 				 struct kvm_page_track_notifier_node *n);
62 void
63 kvm_page_track_unregister_notifier(struct kvm *kvm,
64 				   struct kvm_page_track_notifier_node *n);
65 #else
66 /*
67  * Allow defining a node in a structure even if page tracking is disabled, e.g.
68  * to play nice with testing headers via direct inclusion from the command line.
69  */
70 struct kvm_page_track_notifier_node {};
71 #endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
72 
73 #endif
74