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