[PATCH 11/44] KVM: x86: Move guts of kvm_arch_init() to standalone helper

[Sean Christopherson]

Move the guts of kvm_arch_init() to a new helper, kvm_x86_vendor_init(),
so that VMX can do _all_ arch and vendor initialization before calling
kvm_init().  Calling kvm_init() must be the _very_ last step during init,
as kvm_init() exposes /dev/kvm to userspace, i.e. allows creating VMs.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc at google.com>
---
 arch/x86/include/asm/kvm_host.h |  3 +++
 arch/x86/kvm/svm/svm.c          | 23 +++++++++++++++++++++--
 arch/x86/kvm/vmx/vmx.c          |  9 ++++++++-
 arch/x86/kvm/x86.c              | 15 +++++++++++++--
 4 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 415113dea951..58a7cb8d8e96 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1695,6 +1695,9 @@ extern struct kvm_x86_ops kvm_x86_ops;
 #define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP
 #include <asm/kvm-x86-ops.h>
 
+int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops);
+void kvm_x86_vendor_exit(void);
+
 #define __KVM_HAVE_ARCH_VM_ALLOC
 static inline struct kvm *kvm_arch_alloc_vm(void)
 {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d22a809d9233..f48d07bfc3d7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5132,15 +5132,34 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = {
 
 static int __init svm_init(void)
 {
+	int r;
+
 	__unused_size_checks();
 
-	return kvm_init(&svm_init_ops, sizeof(struct vcpu_svm),
-			__alignof__(struct vcpu_svm), THIS_MODULE);
+	r = kvm_x86_vendor_init(&svm_init_ops);
+	if (r)
+		return r;
+
+	/*
+	 * Common KVM initialization _must_ come last, after this, /dev/kvm is
+	 * exposed to userspace!
+	 */
+	r = kvm_init(&svm_init_ops, sizeof(struct vcpu_svm),
+		     __alignof__(struct vcpu_svm), THIS_MODULE);
+	if (r)
+		goto err_kvm_init;
+
+	return 0;
+
+err_kvm_init:
+	kvm_x86_vendor_exit();
+	return r;
 }
 
 static void __exit svm_exit(void)
 {
 	kvm_exit();
+	kvm_x86_vendor_exit();
 }
 
 module_init(svm_init)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b3fd4049de01..118d9b29b339 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8501,6 +8501,7 @@ static void vmx_exit(void)
 #endif
 
 	kvm_exit();
+	kvm_x86_vendor_exit();
 
 	hv_cleanup_evmcs();
 
@@ -8516,13 +8517,17 @@ static int __init vmx_init(void)
 
 	hv_setup_evmcs();
 
+	r = kvm_x86_vendor_init(&vmx_init_ops);
+	if (r)
+		goto err_x86_init;
+
 	r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx),
 		     __alignof__(struct vcpu_vmx), THIS_MODULE);
 	if (r)
 		goto err_kvm_init;
 
 	/*
-	 * Must be called after kvm_init() so enable_ept is properly set
+	 * Must be called after common x86 init so enable_ept is properly set
 	 * up. Hand the parameter mitigation value in which was stored in
 	 * the pre module init parser. If no parameter was given, it will
 	 * contain 'auto' which will be turned into the default 'cond'
@@ -8559,6 +8564,8 @@ static int __init vmx_init(void)
 err_l1d_flush:
 	vmx_exit();
 err_kvm_init:
+	kvm_x86_vendor_exit();
+err_x86_init:
 	hv_cleanup_evmcs();
 	return r;
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 40d4bfaa17a4..a0ca401d3cdf 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9272,7 +9272,16 @@ static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
 
 int kvm_arch_init(void *opaque)
 {
-	struct kvm_x86_init_ops *ops = opaque;
+	return 0;
+}
+
+void kvm_arch_exit(void)
+{
+
+}
+
+int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
+{
 	u64 host_pat;
 	int r;
 
@@ -9404,8 +9413,9 @@ int kvm_arch_init(void *opaque)
 	kmem_cache_destroy(x86_emulator_cache);
 	return r;
 }
+EXPORT_SYMBOL_GPL(kvm_x86_vendor_init);
 
-void kvm_arch_exit(void)
+void kvm_x86_vendor_exit(void)
 {
 	kvm_unregister_perf_callbacks();
 
@@ -9434,6 +9444,7 @@ void kvm_arch_exit(void)
 	WARN_ON(static_branch_unlikely(&kvm_xen_enabled.key));
 #endif
 }
+EXPORT_SYMBOL_GPL(kvm_x86_vendor_exit);
 
 static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
 {
-- 
2.38.1.431.g37b22c650d-goog