page_track.c File Reference

#include <linux/lockdep.h>
#include <linux/kvm_host.h>
#include <linux/rculist.h>
#include "mmu.h"
#include "mmu_internal.h"
#include "page_track.h"

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Macros
#define	pr_fmt(fmt)   KBUILD_MODNAME ": " fmt

Functions
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)
bool	kvm_gfn_is_write_tracked (struct kvm *kvm, const struct kvm_memory_slot *slot, gfn_t gfn)

Macro Definition Documentation

pr_fmt

#define pr_fmt

(

fmt

)

KBUILD_MODNAME ": " fmt

Definition at line 13 of file page_track.c.

Function Documentation

__kvm_page_track_write_tracking_alloc()

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

static

Definition at line 35 of file page_track.c.

{
    const size_t size = sizeof(*slot->arch.gfn_write_track);
 
    if (!slot->arch.gfn_write_track)
        slot->arch.gfn_write_track = __vcalloc(npages, size,
                               GFP_KERNEL_ACCOUNT);
 
    return slot->arch.gfn_write_track ? 0 : -ENOMEM;
}

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__kvm_write_track_add_gfn()

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

Definition at line 77 of file page_track.c.

{
    lockdep_assert_held_write(&kvm->mmu_lock);
 
    lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
                srcu_read_lock_held(&kvm->srcu));
 
    if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
        return;
 
    update_gfn_write_track(slot, gfn, 1);
 
    /*
     * new track stops large page mapping for the
     * tracked page.
     */
    kvm_mmu_gfn_disallow_lpage(slot, gfn);
 
    if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
        kvm_flush_remote_tlbs(kvm);
}

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__kvm_write_track_remove_gfn()

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

Definition at line 100 of file page_track.c.

{
    lockdep_assert_held_write(&kvm->mmu_lock);
 
    lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
                srcu_read_lock_held(&kvm->srcu));
 
    if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
        return;
 
    update_gfn_write_track(slot, gfn, -1);
 
    /*
     * allow large page mapping for the tracked page
     * after the tracker is gone.
     */
    kvm_mmu_gfn_allow_lpage(slot, gfn);
}

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kvm_gfn_is_write_tracked()

bool kvm_gfn_is_write_tracked	(	struct kvm *	kvm,
		const struct kvm_memory_slot *	slot,
		gfn_t	gfn
	)

Definition at line 123 of file page_track.c.

{
    int index;
 
    if (!slot)
        return false;
 
    if (!kvm_page_track_write_tracking_enabled(kvm))
        return false;
 
    index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
    return !!READ_ONCE(slot->arch.gfn_write_track[index]);
}

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kvm_page_track_create_memslot()

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

Definition at line 47 of file page_track.c.

{
    if (!kvm_page_track_write_tracking_enabled(kvm))
        return 0;
 
    return __kvm_page_track_write_tracking_alloc(slot, npages);
}

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kvm_page_track_free_memslot()

void kvm_page_track_free_memslot

(

struct kvm_memory_slot *

slot

)

Definition at line 29 of file page_track.c.

{
    kvfree(slot->arch.gfn_write_track);
    slot->arch.gfn_write_track = NULL;
}

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kvm_page_track_write_tracking_alloc()

int kvm_page_track_write_tracking_alloc

(

struct kvm_memory_slot *

slot

)

Definition at line 57 of file page_track.c.

{
    return __kvm_page_track_write_tracking_alloc(slot, slot->npages);
}

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kvm_page_track_write_tracking_enabled()

bool kvm_page_track_write_tracking_enabled

(

struct kvm *

kvm

)

Definition at line 23 of file page_track.c.

{
    return IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) ||
           !tdp_enabled || kvm_shadow_root_allocated(kvm);
}

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update_gfn_write_track()

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

static

Definition at line 62 of file page_track.c.

{
    int index, val;
 
    index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
 
    val = slot->arch.gfn_write_track[index];
 
    if (WARN_ON_ONCE(val + count < 0 || val + count > USHRT_MAX))
        return;
 
    slot->arch.gfn_write_track[index] += count;
}

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