Commit c928bfc2 authored by Maciej S. Szmigiero's avatar Maciej S. Szmigiero Committed by Paolo Bonzini
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KVM: Integrate gfn_to_memslot_approx() into search_memslots() 



s390 arch has gfn_to_memslot_approx() which is almost identical to
search_memslots(), differing only in that in case the gfn falls in a hole
one of the memslots bordering the hole is returned.

Add this lookup mode as an option to search_memslots() so we don't have two
almost identical functions for looking up a memslot by its gfn.

Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
[sean: tweaked helper names to keep gfn_to_memslot_approx() in s390]
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <171cd89b52c718dbe180ecd909b4437a64a7e2ec.1638817640.git.maciej.szmigiero@oracle.com>
parent f5756029

arch/s390/kvm/kvm-s390.c

+8 −37
Original line number Diff line number Diff line
@@ -1943,41 +1943,6 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) 
/* for consistency */

#define KVM_S390_CMMA_SIZE_MAX ((u32)KVM_S390_SKEYS_MAX)



/*

 * Similar to gfn_to_memslot, but returns the index of a memslot also when the

 * address falls in a hole. In that case the index of one of the memslots

 * bordering the hole is returned.

 */

static int gfn_to_memslot_approx(struct kvm_memslots *slots, gfn_t gfn)

{

	int start = 0, end = slots->used_slots;

	int slot = atomic_read(&slots->last_used_slot);

	struct kvm_memory_slot *memslots = slots->memslots;



	if (gfn >= memslots[slot].base_gfn &&

	    gfn < memslots[slot].base_gfn + memslots[slot].npages)

		return slot;



	while (start < end) {

		slot = start + (end - start) / 2;



		if (gfn >= memslots[slot].base_gfn)

			end = slot;

		else

			start = slot + 1;

	}



	if (start >= slots->used_slots)

		return slots->used_slots - 1;



	if (gfn >= memslots[start].base_gfn &&

	    gfn < memslots[start].base_gfn + memslots[start].npages) {

		atomic_set(&slots->last_used_slot, start);

	}



	return start;

}



static int kvm_s390_peek_cmma(struct kvm *kvm, struct kvm_s390_cmma_log *args,

			      u8 *res, unsigned long bufsize)

{
@@ -2001,11 +1966,17 @@ static int kvm_s390_peek_cmma(struct kvm *kvm, struct kvm_s390_cmma_log *args, 
	return 0;

}



static struct kvm_memory_slot *gfn_to_memslot_approx(struct kvm_memslots *slots,

						     gfn_t gfn)

{

	return ____gfn_to_memslot(slots, gfn, true);

}



static unsigned long kvm_s390_next_dirty_cmma(struct kvm_memslots *slots,

					      unsigned long cur_gfn)

{

	int slotidx = gfn_to_memslot_approx(slots, cur_gfn);

	struct kvm_memory_slot *ms = slots->memslots + slotidx;

	struct kvm_memory_slot *ms = gfn_to_memslot_approx(slots, cur_gfn);

	int slotidx = ms - slots->memslots;

	unsigned long ofs = cur_gfn - ms->base_gfn;



	if (ms->base_gfn + ms->npages <= cur_gfn) {

include/linux/kvm_host.h

+27 −8
Original line number Diff line number Diff line
@@ -1233,10 +1233,14 @@ try_get_memslot(struct kvm_memslots *slots, int slot_index, gfn_t gfn) 
 * Returns a pointer to the memslot that contains gfn and records the index of

 * the slot in index. Otherwise returns NULL.

 *

 * With "approx" set returns the memslot also when the address falls

 * in a hole. In that case one of the memslots bordering the hole is

 * returned.

 *

 * IMPORTANT: Slots are sorted from highest GFN to lowest GFN!

 */

static inline struct kvm_memory_slot *

search_memslots(struct kvm_memslots *slots, gfn_t gfn, int *index)

search_memslots(struct kvm_memslots *slots, gfn_t gfn, int *index, bool approx)

{

	int start = 0, end = slots->used_slots;

	struct kvm_memory_slot *memslots = slots->memslots;
@@ -1254,22 +1258,26 @@ search_memslots(struct kvm_memslots *slots, gfn_t gfn, int *index) 
			start = slot + 1;

	}



	if (approx && start >= slots->used_slots) {

		*index = slots->used_slots - 1;

		return &memslots[slots->used_slots - 1];

	}



	slot = try_get_memslot(slots, start, gfn);

	if (slot) {

		*index = start;

		return slot;

	}

	if (approx) {

		*index = start;

		return &memslots[start];

	}



	return NULL;

}



/*

 * __gfn_to_memslot() and its descendants are here because it is called from

 * non-modular code in arch/powerpc/kvm/book3s_64_vio{,_hv}.c. gfn_to_memslot()

 * itself isn't here as an inline because that would bloat other code too much.

 */

static inline struct kvm_memory_slot *

__gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn)

____gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn, bool approx)

{

	struct kvm_memory_slot *slot;

	int slot_index = atomic_read(&slots->last_used_slot);
@@ -1278,7 +1286,7 @@ __gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn) 
	if (slot)

		return slot;



	slot = search_memslots(slots, gfn, &slot_index);

	slot = search_memslots(slots, gfn, &slot_index, approx);

	if (slot) {

		atomic_set(&slots->last_used_slot, slot_index);

		return slot;
@@ -1287,6 +1295,17 @@ __gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn) 
	return NULL;

}



/*

 * __gfn_to_memslot() and its descendants are here to allow arch code to inline

 * the lookups in hot paths.  gfn_to_memslot() itself isn't here as an inline

 * because that would bloat other code too much.

 */

static inline struct kvm_memory_slot *

__gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn)

{

	return ____gfn_to_memslot(slots, gfn, false);

}



static inline unsigned long

__gfn_to_hva_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)

{

virt/kvm/kvm_main.c

+1 −1
Original line number Diff line number Diff line
@@ -2141,7 +2141,7 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn 
	 * search_memslots() instead of __gfn_to_memslot() to avoid

	 * thrashing the VM-wide last_used_index in kvm_memslots.

	 */

	slot = search_memslots(slots, gfn, &slot_index);

	slot = search_memslots(slots, gfn, &slot_index, false);

	if (slot) {

		vcpu->last_used_slot = slot_index;

		return slot;