linux/arch/x86/kvm/mmu/page_track.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support KVM gust page tracking
 *
 * This feature allows us to track page access in guest. Currently, only
 * write access is tracked.
 *
 * Copyright(C) 2015 Intel Corporation.
 *
 * Author:
 *   Xiao Guangrong <[email protected]>
 */
#define pr_fmt(fmt) …

#include <linux/lockdep.h>
#include <linux/kvm_host.h>
#include <linux/rculist.h>

#include "mmu.h"
#include "mmu_internal.h"
#include "page_track.h"

static bool kvm_external_write_tracking_enabled(struct kvm *kvm)
{ … }

bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
{ … }

void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
{ … }

static int __kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot,
						 unsigned long npages)
{ … }

int kvm_page_track_create_memslot(struct kvm *kvm,
				  struct kvm_memory_slot *slot,
				  unsigned long npages)
{ … }

int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
{ … }

static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
				   short count)
{ … }

void __kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
			       gfn_t gfn)
{ … }

void __kvm_write_track_remove_gfn(struct kvm *kvm,
				  struct kvm_memory_slot *slot, gfn_t gfn)
{ … }

/*
 * check if the corresponding access on the specified guest page is tracked.
 */
bool kvm_gfn_is_write_tracked(struct kvm *kvm,
			      const struct kvm_memory_slot *slot, gfn_t gfn)
{ … }

#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
void kvm_page_track_cleanup(struct kvm *kvm)
{ … }

int kvm_page_track_init(struct kvm *kvm)
{ … }

static int kvm_enable_external_write_tracking(struct kvm *kvm)
{ … }

/*
 * register the notifier so that event interception for the tracked guest
 * pages can be received.
 */
int kvm_page_track_register_notifier(struct kvm *kvm,
				     struct kvm_page_track_notifier_node *n)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * 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)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * 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 *kvm, gpa_t gpa, const u8 *new, int bytes)
{ … }

/*
 * Notify external page track nodes that a memory region is being removed from
 * the VM, e.g. so that users can free any associated metadata.
 */
void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
{ … }

/*
 * add guest page to the tracking pool so that corresponding access on that
 * page will be intercepted.
 *
 * @kvm: the guest instance we are interested in.
 * @gfn: the guest page.
 */
int kvm_write_track_add_gfn(struct kvm *kvm, gfn_t gfn)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * remove the guest page from the tracking pool which stops the interception
 * of corresponding access on that page.
 *
 * @kvm: the guest instance we are interested in.
 * @gfn: the guest page.
 */
int kvm_write_track_remove_gfn(struct kvm *kvm, gfn_t gfn)
{ … }
EXPORT_SYMBOL_GPL(…);
#endif