KVM: only retrieve memslots once when initializing cache

This will make it a bit simpler to handle multiple address spaces
in gfn_to_hva_cache.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -1937,10 +1937,10 @@ int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
 
-int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
+				       struct gfn_to_hva_cache *ghc,
 				       gpa_t gpa, unsigned long len)
 {
-	struct kvm_memslots *slots = kvm_memslots(kvm);
 	int offset = offset_in_page(gpa);
 	gfn_t start_gfn = gpa >> PAGE_SHIFT;
 	gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
@@ -1950,7 +1950,7 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 	ghc->gpa = gpa;
 	ghc->generation = slots->generation;
 	ghc->len = len;
-	ghc->memslot = gfn_to_memslot(kvm, start_gfn);
+	ghc->memslot = __gfn_to_memslot(slots, start_gfn);
 	ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn, NULL);
 	if (!kvm_is_error_hva(ghc->hva) && nr_pages_needed <= 1) {
 		ghc->hva += offset;
@@ -1960,7 +1960,7 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 		 * verify that the entire region is valid here.
 		 */
 		while (start_gfn <= end_gfn) {
-			ghc->memslot = gfn_to_memslot(kvm, start_gfn);
+			ghc->memslot = __gfn_to_memslot(slots, start_gfn);
 			ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn,
 						   &nr_pages_avail);
 			if (kvm_is_error_hva(ghc->hva))
@@ -1972,6 +1972,13 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 	}
 	return 0;
 }
+
+int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+			      gpa_t gpa, unsigned long len)
+{
+	struct kvm_memslots *slots = kvm_memslots(kvm);
+	return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len);
+}
 EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
 
 int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
@@ -1984,7 +1991,7 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 	BUG_ON(len + offset > ghc->len);
 
 	if (slots->generation != ghc->generation)
-		kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len);
+		__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
 
 	if (unlikely(!ghc->memslot))
 		return kvm_write_guest(kvm, gpa, data, len);
@@ -2017,7 +2024,7 @@ int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 	BUG_ON(len > ghc->len);
 
 	if (slots->generation != ghc->generation)
-		kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len);
+		__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
 
 	if (unlikely(!ghc->memslot))
 		return kvm_read_guest(kvm, ghc->gpa, data, len);