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