KVM: VMX: Move Hyper-V eVMCS initialization to helper

Move Hyper-V's eVMCS initialization to a dedicated helper to clean up
vmx_init(), and add a comment to call out that the Hyper-V init code
doesn't need to be unwound if vmx_init() ultimately fails.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221130230934.1014142-13-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d913973..703d81e 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -523,6 +523,8 @@ static inline void vmx_segment_cache_clear(struct vcpu_vmx *vmx)
 static unsigned long host_idt_base;
 
 #if IS_ENABLED(CONFIG_HYPERV)
+static struct kvm_x86_ops vmx_x86_ops __initdata;
+
 static bool __read_mostly enlightened_vmcs = true;
 module_param(enlightened_vmcs, bool, 0444);
 
@@ -551,6 +553,43 @@ static int hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu)
        return 0;
 }
 
+static __init void hv_init_evmcs(void)
+{
+       int cpu;
+
+       if (!enlightened_vmcs)
+               return;
+
+       /*
+        * Enlightened VMCS usage should be recommended and the host needs
+        * to support eVMCS v1 or above.
+        */
+       if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED &&
+           (ms_hyperv.nested_features & HV_X64_ENLIGHTENED_VMCS_VERSION) >=
+            KVM_EVMCS_VERSION) {
+
+               /* Check that we have assist pages on all online CPUs */
+               for_each_online_cpu(cpu) {
+                       if (!hv_get_vp_assist_page(cpu)) {
+                               enlightened_vmcs = false;
+                               break;
+                       }
+               }
+
+               if (enlightened_vmcs) {
+                       pr_info("KVM: vmx: using Hyper-V Enlightened VMCS\n");
+                       static_branch_enable(&enable_evmcs);
+               }
+
+               if (ms_hyperv.nested_features & HV_X64_NESTED_DIRECT_FLUSH)
+                       vmx_x86_ops.enable_l2_tlb_flush
+                               = hv_enable_l2_tlb_flush;
+
+       } else {
+               enlightened_vmcs = false;
+       }
+}
+
 static void hv_reset_evmcs(void)
 {
        struct hv_vp_assist_page *vp_ap;
@@ -577,6 +616,7 @@ static void hv_reset_evmcs(void)
 }
 
 #else /* IS_ENABLED(CONFIG_HYPERV) */
+static void hv_init_evmcs(void) {}
 static void hv_reset_evmcs(void) {}
 #endif /* IS_ENABLED(CONFIG_HYPERV) */
 
@@ -8543,38 +8583,11 @@ static int __init vmx_init(void)
 {
        int r, cpu;
 
-#if IS_ENABLED(CONFIG_HYPERV)
        /*
-        * Enlightened VMCS usage should be recommended and the host needs
-        * to support eVMCS v1 or above. We can also disable eVMCS support
-        * with module parameter.
+        * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
+        * to unwind if a later step fails.
         */
-       if (enlightened_vmcs &&
-           ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED &&
-           (ms_hyperv.nested_features & HV_X64_ENLIGHTENED_VMCS_VERSION) >=
-           KVM_EVMCS_VERSION) {
-
-               /* Check that we have assist pages on all online CPUs */
-               for_each_online_cpu(cpu) {
-                       if (!hv_get_vp_assist_page(cpu)) {
-                               enlightened_vmcs = false;
-                               break;
-                       }
-               }
-
-               if (enlightened_vmcs) {
-                       pr_info("KVM: vmx: using Hyper-V Enlightened VMCS\n");
-                       static_branch_enable(&enable_evmcs);
-               }
-
-               if (ms_hyperv.nested_features & HV_X64_NESTED_DIRECT_FLUSH)
-                       vmx_x86_ops.enable_l2_tlb_flush
-                               = hv_enable_l2_tlb_flush;
-
-       } else {
-               enlightened_vmcs = false;
-       }
-#endif
+       hv_init_evmcs();
 
        r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx),
                     __alignof__(struct vcpu_vmx), THIS_MODULE);