KVM: PPC: Move memslot memory allocation into prepare_memory_region()

Allocate the rmap array during kvm_arch_prepare_memory_region() to pave
the way for removing kvm_arch_create_memslot() altogether.  Moving PPC's
memory allocation only changes the order of kernel memory allocations
between PPC and common KVM code.

No functional change intended.
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/powerpc/include/asm/kvm_ppc.h

@@ -202,12 +202,10 @@ extern void kvmppc_core_destroy_vm(struct kvm *kvm);
 extern void kvmppc_core_free_memslot(struct kvm *kvm,
 				     struct kvm_memory_slot *free,
 				     struct kvm_memory_slot *dont);
-extern int kvmppc_core_create_memslot(struct kvm *kvm,
-				      struct kvm_memory_slot *slot,
-				      unsigned long npages);
 extern int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 				struct kvm_memory_slot *memslot,
-				const struct kvm_userspace_memory_region *mem);
+				const struct kvm_userspace_memory_region *mem,
+				enum kvm_mr_change change);
 extern void kvmppc_core_commit_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
 				const struct kvm_memory_slot *old,
@@ -280,7 +278,8 @@ struct kvmppc_ops {
 	void (*flush_memslot)(struct kvm *kvm, struct kvm_memory_slot *memslot);
 	int (*prepare_memory_region)(struct kvm *kvm,
 				     struct kvm_memory_slot *memslot,
-				     const struct kvm_userspace_memory_region *mem);
+				     const struct kvm_userspace_memory_region *mem,
+				     enum kvm_mr_change change);
 	void (*commit_memory_region)(struct kvm *kvm,
 				     const struct kvm_userspace_memory_region *mem,
 				     const struct kvm_memory_slot *old,
@@ -294,8 +293,6 @@ struct kvmppc_ops {
 	void (*mmu_destroy)(struct kvm_vcpu *vcpu);
 	void (*free_memslot)(struct kvm_memory_slot *free,
 			     struct kvm_memory_slot *dont);
-	int (*create_memslot)(struct kvm_memory_slot *slot,
-			      unsigned long npages);
 	int (*init_vm)(struct kvm *kvm);
 	void (*destroy_vm)(struct kvm *kvm);
 	int (*get_smmu_info)(struct kvm *kvm, struct kvm_ppc_smmu_info *info);

arch/powerpc/kvm/book3s.c

@@ -810,12 +810,6 @@ void kvmppc_core_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 	kvm->arch.kvm_ops->free_memslot(free, dont);
 }
 
-int kvmppc_core_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
-			       unsigned long npages)
-{
-	return kvm->arch.kvm_ops->create_memslot(slot, npages);
-}
-
 void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 	kvm->arch.kvm_ops->flush_memslot(kvm, memslot);
@@ -823,9 +817,11 @@ void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
 
 int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 				struct kvm_memory_slot *memslot,
-				const struct kvm_userspace_memory_region *mem)
+				const struct kvm_userspace_memory_region *mem,
+				enum kvm_mr_change change)
 {
-	return kvm->arch.kvm_ops->prepare_memory_region(kvm, memslot, mem);
+	return kvm->arch.kvm_ops->prepare_memory_region(kvm, memslot, mem,
+							change);
 }
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,

arch/powerpc/kvm/book3s_hv.c

@@ -4456,20 +4456,20 @@ static void kvmppc_core_free_memslot_hv(struct kvm_memory_slot *free,
 	}
 }
 
-static int kvmppc_core_create_memslot_hv(struct kvm_memory_slot *slot,
-					 unsigned long npages)
+static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm,
+					struct kvm_memory_slot *slot,
+					const struct kvm_userspace_memory_region *mem,
+					enum kvm_mr_change change)
 {
-	slot->arch.rmap = vzalloc(array_size(npages, sizeof(*slot->arch.rmap)));
-	if (!slot->arch.rmap)
-		return -ENOMEM;
+	unsigned long npages = mem->memory_size >> PAGE_SHIFT;
 
-	return 0;
-}
+	if (change == KVM_MR_CREATE) {
+		slot->arch.rmap = vzalloc(array_size(npages,
+					  sizeof(*slot->arch.rmap)));
+		if (!slot->arch.rmap)
+			return -ENOMEM;
+	}
 
-static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm,
-					struct kvm_memory_slot *memslot,
-					const struct kvm_userspace_memory_region *mem)
-{
 	return 0;
 }
 
@@ -5528,7 +5528,6 @@ static struct kvmppc_ops kvm_ops_hv = {
 	.set_spte_hva = kvm_set_spte_hva_hv,
 	.mmu_destroy  = kvmppc_mmu_destroy_hv,
 	.free_memslot = kvmppc_core_free_memslot_hv,
-	.create_memslot = kvmppc_core_create_memslot_hv,
 	.init_vm =  kvmppc_core_init_vm_hv,
 	.destroy_vm = kvmppc_core_destroy_vm_hv,
 	.get_smmu_info = kvm_vm_ioctl_get_smmu_info_hv,

arch/powerpc/kvm/book3s_pr.c

@@ -1927,7 +1927,8 @@ static void kvmppc_core_flush_memslot_pr(struct kvm *kvm,
 
 static int kvmppc_core_prepare_memory_region_pr(struct kvm *kvm,
 					struct kvm_memory_slot *memslot,
-					const struct kvm_userspace_memory_region *mem)
+					const struct kvm_userspace_memory_region *mem,
+					enum kvm_mr_change change)
 {
 	return 0;
 }
@@ -1947,13 +1948,6 @@ static void kvmppc_core_free_memslot_pr(struct kvm_memory_slot *free,
 	return;
 }
 
-static int kvmppc_core_create_memslot_pr(struct kvm_memory_slot *slot,
-					 unsigned long npages)
-{
-	return 0;
-}
-
-
 #ifdef CONFIG_PPC64
 static int kvm_vm_ioctl_get_smmu_info_pr(struct kvm *kvm,
 					 struct kvm_ppc_smmu_info *info)
@@ -2099,7 +2093,6 @@ static struct kvmppc_ops kvm_ops_pr = {
 	.set_spte_hva = kvm_set_spte_hva_pr,
 	.mmu_destroy  = kvmppc_mmu_destroy_pr,
 	.free_memslot = kvmppc_core_free_memslot_pr,
-	.create_memslot = kvmppc_core_create_memslot_pr,
 	.init_vm = kvmppc_core_init_vm_pr,
 	.destroy_vm = kvmppc_core_destroy_vm_pr,
 	.get_smmu_info = kvm_vm_ioctl_get_smmu_info_pr,

arch/powerpc/kvm/booke.c

@@ -1776,15 +1776,10 @@ void kvmppc_core_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 {
 }
 
-int kvmppc_core_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
-			       unsigned long npages)
-{
-	return 0;
-}
-
 int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 				      struct kvm_memory_slot *memslot,
-				      const struct kvm_userspace_memory_region *mem)
+				      const struct kvm_userspace_memory_region *mem,
+				      enum kvm_mr_change change)
 {
 	return 0;
 }

arch/powerpc/kvm/powerpc.c

@@ -694,7 +694,7 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
 			    unsigned long npages)
 {
-	return kvmppc_core_create_memslot(kvm, slot, npages);
+	return 0;
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
@@ -702,7 +702,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				   const struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
-	return kvmppc_core_prepare_memory_region(kvm, memslot, mem);
+	return kvmppc_core_prepare_memory_region(kvm, memslot, mem, change);
 }
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,