KVM: nVMX: Separate logic allocating shadow vmcs to a function

No functionality change.
This is done as a preparation for VMCS shadowing virtualization.

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 098926a..cbe31b9 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7905,10 +7905,35 @@ static int nested_vmx_get_vmptr(struct kvm_vcpu *vcpu, gpa_t *vmpointer)
        return 0;
 }
 
+/*
+ * Allocate a shadow VMCS and associate it with the currently loaded
+ * VMCS, unless such a shadow VMCS already exists. The newly allocated
+ * VMCS is also VMCLEARed, so that it is ready for use.
+ */
+static struct vmcs *alloc_shadow_vmcs(struct kvm_vcpu *vcpu)
+{
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
+       struct loaded_vmcs *loaded_vmcs = vmx->loaded_vmcs;
+
+       /*
+        * We should allocate a shadow vmcs for vmcs01 only when L1
+        * executes VMXON and free it when L1 executes VMXOFF.
+        * As it is invalid to execute VMXON twice, we shouldn't reach
+        * here when vmcs01 already have an allocated shadow vmcs.
+        */
+       WARN_ON(loaded_vmcs == &vmx->vmcs01 && loaded_vmcs->shadow_vmcs);
+
+       if (!loaded_vmcs->shadow_vmcs) {
+               loaded_vmcs->shadow_vmcs = alloc_vmcs(true);
+               if (loaded_vmcs->shadow_vmcs)
+                       vmcs_clear(loaded_vmcs->shadow_vmcs);
+       }
+       return loaded_vmcs->shadow_vmcs;
+}
+
 static int enter_vmx_operation(struct kvm_vcpu *vcpu)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
-       struct vmcs *shadow_vmcs;
        int r;
 
        r = alloc_loaded_vmcs(&vmx->nested.vmcs02);
@@ -7923,14 +7948,8 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
        if (!vmx->nested.cached_shadow_vmcs12)
                goto out_cached_shadow_vmcs12;
 
-       if (enable_shadow_vmcs) {
-               shadow_vmcs = alloc_vmcs(true);
-               if (!shadow_vmcs)
-                       goto out_shadow_vmcs;
-               /* init shadow vmcs */
-               vmcs_clear(shadow_vmcs);
-               vmx->vmcs01.shadow_vmcs = shadow_vmcs;
-       }
+       if (enable_shadow_vmcs && !alloc_shadow_vmcs(vcpu))
+               goto out_shadow_vmcs;
 
        hrtimer_init(&vmx->nested.preemption_timer, CLOCK_MONOTONIC,
                     HRTIMER_MODE_REL_PINNED);