KVM: PPC: Allocate vcpu struct in common PPC code

Move allocation of all flavors of PPC vCPUs to common PPC code.  All
variants either allocate 'struct kvm_vcpu' directly, or require that
the embedded 'struct kvm_vcpu' member be located at offset 0, i.e.
guarantee that the allocation can be directly interpreted as a 'struct
kvm_vcpu' object.

Remove the message from the build-time assertion regarding placement of
the struct, as compatibility with the arch usercopy region is no longer
the sole dependent on 'struct kvm_vcpu' being at offset zero.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/powerpc/include/asm/kvm_ppc.h

@@ -119,7 +119,7 @@ extern int kvmppc_xlate(struct kvm_vcpu *vcpu, ulong eaddr,
 			enum xlate_instdata xlid, enum xlate_readwrite xlrw,
 			struct kvmppc_pte *pte);
 
-extern struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm,
+extern int kvmppc_core_vcpu_create(struct kvm *kvm, struct kvm_vcpu *vcpu,
 				   unsigned int id);
 extern void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu);
 extern int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu);
@@ -274,7 +274,8 @@ struct kvmppc_ops {
 	void (*inject_interrupt)(struct kvm_vcpu *vcpu, int vec, u64 srr1_flags);
 	void (*set_msr)(struct kvm_vcpu *vcpu, u64 msr);
 	int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
-	struct kvm_vcpu *(*vcpu_create)(struct kvm *kvm, unsigned int id);
+	int (*vcpu_create)(struct kvm *kvm, struct kvm_vcpu *vcpu,
+			   unsigned int id);
 	void (*vcpu_free)(struct kvm_vcpu *vcpu);
 	int (*check_requests)(struct kvm_vcpu *vcpu);
 	int (*get_dirty_log)(struct kvm *kvm, struct kvm_dirty_log *log);

arch/powerpc/kvm/book3s.c

@@ -789,9 +789,10 @@ void kvmppc_decrementer_func(struct kvm_vcpu *vcpu)
 	kvm_vcpu_kick(vcpu);
 }
 
-struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id)
+int kvmppc_core_vcpu_create(struct kvm *kvm, struct kvm_vcpu *vcpu,
+			    unsigned int id)
 {
-	return kvm->arch.kvm_ops->vcpu_create(kvm, id);
+	return kvm->arch.kvm_ops->vcpu_create(kvm, vcpu, id);
 }
 
 void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu)

arch/powerpc/kvm/book3s_hv.c

@@ -2271,22 +2271,16 @@ static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
 }
 #endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
 
-static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
+static int kvmppc_core_vcpu_create_hv(struct kvm *kvm, struct kvm_vcpu *vcpu,
 				      unsigned int id)
 {
-	struct kvm_vcpu *vcpu;
 	int err;
 	int core;
 	struct kvmppc_vcore *vcore;
 
-	err = -ENOMEM;
-	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
-	if (!vcpu)
-		goto out;
-
 	err = kvm_vcpu_init(vcpu, kvm, id);
 	if (err)
-		goto free_vcpu;
+		return err;
 
 	vcpu->arch.shared = &vcpu->arch.shregs;
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
@@ -2383,14 +2377,11 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
 
 	debugfs_vcpu_init(vcpu, id);
 
-	return vcpu;
+	return 0;
 
 uninit_vcpu:
 	kvm_vcpu_uninit(vcpu);
-free_vcpu:
-	kmem_cache_free(kvm_vcpu_cache, vcpu);
-out:
-	return ERR_PTR(err);
+	return err;
 }
 
 static int kvmhv_set_smt_mode(struct kvm *kvm, unsigned long smt_mode,
@@ -2445,7 +2436,6 @@ static void kvmppc_core_vcpu_free_hv(struct kvm_vcpu *vcpu)
 	unpin_vpa(vcpu->kvm, &vcpu->arch.vpa);
 	spin_unlock(&vcpu->arch.vpa_update_lock);
 	kvm_vcpu_uninit(vcpu);
-	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
 static int kvmppc_core_check_requests_hv(struct kvm_vcpu *vcpu)

arch/powerpc/kvm/book3s_pr.c

@@ -1744,21 +1744,16 @@ static int kvmppc_set_one_reg_pr(struct kvm_vcpu *vcpu, u64 id,
 	return r;
 }
 
-static struct kvm_vcpu *kvmppc_core_vcpu_create_pr(struct kvm *kvm,
+static int kvmppc_core_vcpu_create_pr(struct kvm *kvm, struct kvm_vcpu *vcpu,
 				      unsigned int id)
 {
 	struct kvmppc_vcpu_book3s *vcpu_book3s;
-	struct kvm_vcpu *vcpu;
 	int err = -ENOMEM;
 	unsigned long p;
 
-	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
-	if (!vcpu)
-		goto out;
-
 	vcpu_book3s = vzalloc(sizeof(struct kvmppc_vcpu_book3s));
 	if (!vcpu_book3s)
-		goto free_vcpu;
+		goto out;
 	vcpu->arch.book3s = vcpu_book3s;
 
 #ifdef CONFIG_KVM_BOOK3S_32_HANDLER
@@ -1808,7 +1803,7 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_pr(struct kvm *kvm,
 	if (err < 0)
 		goto free_shared_page;
 
-	return vcpu;
+	return 0;
 
 free_shared_page:
 	free_page((unsigned long)vcpu->arch.shared);
@@ -1820,10 +1815,8 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_pr(struct kvm *kvm,
 free_vcpu3s:
 #endif
 	vfree(vcpu_book3s);
-free_vcpu:
-	kmem_cache_free(kvm_vcpu_cache, vcpu);
 out:
-	return ERR_PTR(err);
+	return err;
 }
 
 static void kvmppc_core_vcpu_free_pr(struct kvm_vcpu *vcpu)
@@ -1836,7 +1829,6 @@ static void kvmppc_core_vcpu_free_pr(struct kvm_vcpu *vcpu)
 	kfree(vcpu->arch.shadow_vcpu);
 #endif
 	vfree(vcpu_book3s);
-	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
 static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)

arch/powerpc/kvm/booke.c

@@ -2114,9 +2114,10 @@ int kvmppc_core_init_vm(struct kvm *kvm)
 	return kvm->arch.kvm_ops->init_vm(kvm);
 }
 
-struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id)
+int kvmppc_core_vcpu_create(struct kvm *kvm, struct kvm_vcpu *vcpu,
+			    unsigned int id)
 {
-	return kvm->arch.kvm_ops->vcpu_create(kvm, id);
+	return kvm->arch.kvm_ops->vcpu_create(kvm, vcpu, id);
 }
 
 void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu)

arch/powerpc/kvm/e500.c

@@ -433,26 +433,18 @@ static int kvmppc_set_one_reg_e500(struct kvm_vcpu *vcpu, u64 id,
 	return r;
 }
 
-static struct kvm_vcpu *kvmppc_core_vcpu_create_e500(struct kvm *kvm,
+static int kvmppc_core_vcpu_create_e500(struct kvm *kvm, struct kvm_vcpu *vcpu,
 					unsigned int id)
 {
 	struct kvmppc_vcpu_e500 *vcpu_e500;
-	struct kvm_vcpu *vcpu;
 	int err;
 
-	BUILD_BUG_ON_MSG(offsetof(struct kvmppc_vcpu_e500, vcpu) != 0,
-		"struct kvm_vcpu must be at offset 0 for arch usercopy region");
+	BUILD_BUG_ON(offsetof(struct kvmppc_vcpu_e500, vcpu) != 0);
+	vcpu_e500 = to_e500(vcpu);
 
-	vcpu_e500 = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
-	if (!vcpu_e500) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	vcpu = &vcpu_e500->vcpu;
 	err = kvm_vcpu_init(vcpu, kvm, id);
 	if (err)
-		goto free_vcpu;
+		return err;
 
 	if (kvmppc_e500_id_table_alloc(vcpu_e500) == NULL) {
 		err = -ENOMEM;
@@ -469,7 +461,7 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_e500(struct kvm *kvm,
 		goto uninit_tlb;
 	}
 
-	return vcpu;
+	return 0;
 
 uninit_tlb:
 	kvmppc_e500_tlb_uninit(vcpu_e500);
@@ -477,10 +469,7 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_e500(struct kvm *kvm,
 	kvmppc_e500_id_table_free(vcpu_e500);
 uninit_vcpu:
 	kvm_vcpu_uninit(vcpu);
-free_vcpu:
-	kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
-out:
-	return ERR_PTR(err);
+	return err;
 }
 
 static void kvmppc_core_vcpu_free_e500(struct kvm_vcpu *vcpu)
@@ -491,7 +480,6 @@ static void kvmppc_core_vcpu_free_e500(struct kvm_vcpu *vcpu)
 	kvmppc_e500_tlb_uninit(vcpu_e500);
 	kvmppc_e500_id_table_free(vcpu_e500);
 	kvm_vcpu_uninit(vcpu);
-	kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
 }
 
 static int kvmppc_core_init_vm_e500(struct kvm *kvm)

arch/powerpc/kvm/e500mc.c

@@ -301,28 +301,21 @@ static int kvmppc_set_one_reg_e500mc(struct kvm_vcpu *vcpu, u64 id,
 	return r;
 }
 
-static struct kvm_vcpu *kvmppc_core_vcpu_create_e500mc(struct kvm *kvm,
+static int kvmppc_core_vcpu_create_e500mc(struct kvm *kvm, struct kvm_vcpu *vcpu,
 					  unsigned int id)
 {
 	struct kvmppc_vcpu_e500 *vcpu_e500;
-	struct kvm_vcpu *vcpu;
 	int err;
 
 	BUILD_BUG_ON(offsetof(struct kvmppc_vcpu_e500, vcpu) != 0);
-
-	vcpu_e500 = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
-	if (!vcpu_e500) {
-		err = -ENOMEM;
-		goto out;
-	}
-	vcpu = &vcpu_e500->vcpu;
+	vcpu_e500 = to_e500(vcpu);
 
 	/* Invalid PIR value -- this LPID dosn't have valid state on any cpu */
 	vcpu->arch.oldpir = 0xffffffff;
 
 	err = kvm_vcpu_init(vcpu, kvm, id);
 	if (err)
-		goto free_vcpu;
+		return err;
 
 	err = kvmppc_e500_tlb_init(vcpu_e500);
 	if (err)
@@ -334,17 +327,13 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_e500mc(struct kvm *kvm,
 		goto uninit_tlb;
 	}
 
-	return vcpu;
+	return 0;
 
 uninit_tlb:
 	kvmppc_e500_tlb_uninit(vcpu_e500);
 uninit_vcpu:
 	kvm_vcpu_uninit(vcpu);
-
-free_vcpu:
-	kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
-out:
-	return ERR_PTR(err);
+	return err;
 }
 
 static void kvmppc_core_vcpu_free_e500mc(struct kvm_vcpu *vcpu)
@@ -354,7 +343,6 @@ static void kvmppc_core_vcpu_free_e500mc(struct kvm_vcpu *vcpu)
 	free_page((unsigned long)vcpu->arch.shared);
 	kvmppc_e500_tlb_uninit(vcpu_e500);
 	kvm_vcpu_uninit(vcpu);
-	kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
 }
 
 static int kvmppc_core_init_vm_e500mc(struct kvm *kvm)

arch/powerpc/kvm/powerpc.c

@@ -723,12 +723,23 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
 	struct kvm_vcpu *vcpu;
-	vcpu = kvmppc_core_vcpu_create(kvm, id);
-	if (!IS_ERR(vcpu)) {
+	int err;
+
+	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+	if (!vcpu)
+		return ERR_PTR(-ENOMEM);
+
+	err = kvmppc_core_vcpu_create(kvm, vcpu, id);
+	if (err)
+		goto free_vcpu;
+
 	vcpu->arch.wqp = &vcpu->wq;
 	kvmppc_create_vcpu_debugfs(vcpu, id);
-	}
 	return vcpu;
+
+free_vcpu:
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
+	return ERR_PTR(err);
 }
 
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
@@ -758,6 +769,8 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 	}
 
 	kvmppc_core_vcpu_free(vcpu);
+
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)