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 */
15struct kvm_page_track_notifier_head {
16 struct srcu_struct track_srcu;
17 struct hlist_head track_notifier_list;
18};
19
20struct 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
47int kvm_page_track_register_notifier(struct kvm *kvm,
48 struct kvm_page_track_notifier_node *n);
49void kvm_page_track_unregister_notifier(struct kvm *kvm,
50 struct kvm_page_track_notifier_node *n);
51
52int kvm_write_track_add_gfn(struct kvm *kvm, gfn_t gfn);
53int 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 */
59struct kvm_page_track_notifier_node {};
60#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
61
62#endif
63