Commit 9b9b1492 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Avi Kivity
Browse files

KVM: MMU: Split gfn_to_rmap() into two functions 



rmap_write_protect() calls gfn_to_rmap() for each level with gfn fixed.
This results in calling gfn_to_memslot() repeatedly with that gfn.

This patch introduces __gfn_to_rmap() which takes the slot as an
argument to avoid this.

This is also needed for the following dirty logging optimization.

Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent d6eebf8b

arch/x86/kvm/mmu.c

+17 −9
Original line number Diff line number Diff line
@@ -958,23 +958,29 @@ static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn) 
	}

}



/*

 * Take gfn and return the reverse mapping to it.

 */

static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)

static unsigned long *__gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level,

				    struct kvm_memory_slot *slot)

{

	struct kvm_memory_slot *slot;

	struct kvm_lpage_info *linfo;



	slot = gfn_to_memslot(kvm, gfn);

	if (likely(level == PT_PAGE_TABLE_LEVEL))

		return &slot->rmap[gfn - slot->base_gfn];



	linfo = lpage_info_slot(gfn, slot, level);



	return &linfo->rmap_pde;

}



/*

 * Take gfn and return the reverse mapping to it.

 */

static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)

{

	struct kvm_memory_slot *slot;



	slot = gfn_to_memslot(kvm, gfn);

	return __gfn_to_rmap(kvm, gfn, level, slot);

}



static bool rmap_can_add(struct kvm_vcpu *vcpu)

{

	struct kvm_mmu_memory_cache *cache;
@@ -1019,12 +1025,14 @@ static void drop_spte(struct kvm *kvm, u64 *sptep) 


static int rmap_write_protect(struct kvm *kvm, u64 gfn)

{

	struct kvm_memory_slot *slot;

	unsigned long *rmapp;

	u64 *spte;

	int i, write_protected = 0;



	rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);

	slot = gfn_to_memslot(kvm, gfn);



	rmapp = __gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL, slot);

	spte = rmap_next(kvm, rmapp, NULL);

	while (spte) {

		BUG_ON(!(*spte & PT_PRESENT_MASK));
@@ -1039,7 +1047,7 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn) 
	/* check for huge page mappings */

	for (i = PT_DIRECTORY_LEVEL;

	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {

		rmapp = gfn_to_rmap(kvm, gfn, i);

		rmapp = __gfn_to_rmap(kvm, gfn, i, slot);

		spte = rmap_next(kvm, rmapp, NULL);

		while (spte) {

			BUG_ON(!(*spte & PT_PRESENT_MASK));

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