KVM: TDX: create/destroy VM structure

As the first step to create TDX guest, create/destroy VM struct.  Assign
Host Key ID (HKID) to the TDX guest for memory encryption and allocate
extra pages for the TDX guest. On destruction, free allocated pages, and
HKID.

Add a second kvm_x86_ops hook in kvm_arch_vm_destroy() to support TDX's
destruction path, which needs to first put the VM into a teardown state,
then free per-vCPU resources, and finally free per-VM resources.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>

arch/x86/include/asm/kvm-x86-ops.h

@@ -21,6 +21,7 @@ KVM_X86_OP(vcpu_after_set_cpuid)
 KVM_X86_OP(is_vm_type_supported)
 KVM_X86_OP(vm_init)
 KVM_X86_OP_NULL(vm_destroy)
+KVM_X86_OP_NULL(vm_free)
 KVM_X86_OP(vcpu_create)
 KVM_X86_OP(vcpu_free)
 KVM_X86_OP(vcpu_reset)

arch/x86/include/asm/kvm_host.h

@@ -1318,6 +1318,7 @@ struct kvm_x86_ops {
 	unsigned int vm_size;
 	int (*vm_init)(struct kvm *kvm);
 	void (*vm_destroy)(struct kvm *kvm);
+	void (*vm_free)(struct kvm *kvm);
 
 	/* Create, but do not attach this VCPU */
 	int (*vcpu_create)(struct kvm_vcpu *vcpu);

arch/x86/kvm/vmx/main.c

@@ -3,6 +3,7 @@
 
 #include "x86_ops.h"
 #include "vmx.h"
+#include "tdx.h"
 #include "nested.h"
 #include "pmu.h"
 
@@ -28,6 +29,28 @@ static __init int vt_hardware_setup(void)
 	return 0;
 }
 
+static int vt_vm_init(struct kvm *kvm)
+{
+	if (kvm->arch.vm_type == KVM_X86_TDX_VM)
+		return tdx_vm_init(kvm);
+
+	return vmx_vm_init(kvm);
+}
+
+static void vt_vm_destroy(struct kvm *kvm)
+{
+	if (is_td(kvm))
+		return tdx_vm_teardown(kvm);
+}
+
+static void vt_vm_free(struct kvm *kvm)
+{
+	if (is_td(kvm)) {
+		tdx_vm_free(kvm);
+		return;
+	}
+}
+
 static int vt_mem_enc_op_dev(void __user *argp)
 {
 	if (!enable_tdx)
@@ -54,7 +77,9 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 
 	.is_vm_type_supported = vt_is_vm_type_supported,
 	.vm_size = sizeof(struct kvm_vmx),
-	.vm_init = vmx_vm_init,
+	.vm_init = vt_vm_init,
+	.vm_destroy = vt_vm_destroy,
+	.vm_free = vt_vm_free,
 
 	.vcpu_create = vmx_create_vcpu,
 	.vcpu_free = vmx_free_vcpu,