KVM: x86: Move guts of kvm_arch_init() to standalone helper

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@google.com>
Message-Id: <20221130230934.1014142-14-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c70690b..4899505 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1751,6 +1751,9 @@ 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 9a194aa..a477eee 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5097,15 +5097,34 @@ 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 703d81e..1e2eab6 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8572,6 +8572,7 @@ static void vmx_exit(void)
 #endif
 
        kvm_exit();
+       kvm_x86_vendor_exit();
 
        vmx_cleanup_l1d_flush();
 
@@ -8589,23 +8590,25 @@ static int __init vmx_init(void)
         */
        hv_init_evmcs();
 
+       r = kvm_x86_vendor_init(&vmx_init_ops);
+       if (r)
+               return r;
+
        r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx),
                     __alignof__(struct vcpu_vmx), THIS_MODULE);
        if (r)
-               return 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'
         * mitigation mode.
         */
        r = vmx_setup_l1d_flush(vmentry_l1d_flush_param);
-       if (r) {
-               vmx_exit();
-               return r;
-       }
+       if (r)
+               goto err_l1d_flush;
 
        vmx_setup_fb_clear_ctrl();
 
@@ -8630,5 +8633,11 @@ static int __init vmx_init(void)
                allow_smaller_maxphyaddr = true;
 
        return 0;
+
+err_l1d_flush:
+       vmx_exit();
+err_kvm_init:
+       kvm_x86_vendor_exit();
+       return r;
 }
 module_init(vmx_init);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 089f0ee..9837f57 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9293,7 +9293,16 @@ 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;
 
@@ -9425,8 +9434,9 @@ out_free_x86_emulator_cache:
        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();
 
@@ -9456,6 +9466,7 @@ 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)
 {