KVM: TDX: create/destroy VM structure

Implement managing the TDX private KeyID to implement, create, destroy
and free for a TDX guest.

When creating at TDX guest, assign a TDX private KeyID for the TDX guest
for memory encryption, and allocate pages for the guest. These are used
for the Trust Domain Root (TDR) and Trust Domain Control Structure (TDCS).

On destruction, free the allocated pages, and the KeyID.

Before tearing down the private page tables, TDX requires the guest TD to
be destroyed by reclaiming the KeyID. Do it in the vm_pre_destroy() kvm_x86_ops
hook. The TDR control structures can be freed in the vm_destroy() hook,
which runs last.

Co-developed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 - Fix build issue in kvm-coco-queue
 - Init ret earlier to fix __tdx_td_init() error handling. (Chao)
 - Standardize -EAGAIN for __tdx_td_init() retry errors (Rick)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: yamahata

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

@@ -21,6 +21,7 @@ KVM_X86_OP(has_emulated_msr)
 KVM_X86_OP(vcpu_after_set_cpuid)
 KVM_X86_OP(vm_init)
 KVM_X86_OP_OPTIONAL(vm_destroy)
+KVM_X86_OP_OPTIONAL(vm_pre_destroy)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_precreate)
 KVM_X86_OP(vcpu_create)
 KVM_X86_OP(vcpu_free)

arch/x86/include/asm/kvm_host.h

@@ -1665,6 +1665,7 @@ struct kvm_x86_ops {
 	unsigned int vm_size;
 	int (*vm_init)(struct kvm *kvm);
 	void (*vm_destroy)(struct kvm *kvm);
+	void (*vm_pre_destroy)(struct kvm *kvm);
 
 	/* Create, but do not attach this VCPU */
 	int (*vcpu_precreate)(struct kvm *kvm);

arch/x86/kvm/Kconfig

@@ -94,6 +94,8 @@ config KVM_SW_PROTECTED_VM
 config KVM_INTEL
 	tristate "KVM for Intel (and compatible) processors support"
 	depends on KVM && IA32_FEAT_CTL
+	select KVM_GENERIC_PRIVATE_MEM if INTEL_TDX_HOST
+	select KVM_GENERIC_MEMORY_ATTRIBUTES if INTEL_TDX_HOST
 	help
 	  Provides support for KVM on processors equipped with Intel's VT
 	  extensions, a.k.a. Virtual Machine Extensions (VMX).

arch/x86/kvm/vmx/main.c

@@ -41,6 +41,28 @@ static __init int vt_hardware_setup(void)
 	return 0;
 }
 
+static int vt_vm_init(struct kvm *kvm)
+{
+	if (is_td(kvm))
+		return tdx_vm_init(kvm);
+
+	return vmx_vm_init(kvm);
+}
+
+static void vt_vm_pre_destroy(struct kvm *kvm)
+{
+	if (is_td(kvm))
+		return tdx_mmu_release_hkid(kvm);
+}
+
+static void vt_vm_destroy(struct kvm *kvm)
+{
+	if (is_td(kvm))
+               return tdx_vm_destroy(kvm);
+
+       vmx_vm_destroy(kvm);
+}
+
 static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 {
 	if (!is_td(kvm))
@@ -72,8 +94,10 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.has_emulated_msr = vmx_has_emulated_msr,
 
 	.vm_size = sizeof(struct kvm_vmx),
-	.vm_init = vmx_vm_init,
-	.vm_destroy = vmx_vm_destroy,
+
+	.vm_init = vt_vm_init,
+	.vm_pre_destroy = vt_vm_pre_destroy,
+	.vm_destroy = vt_vm_destroy,
 
 	.vcpu_precreate = vmx_vcpu_precreate,
 	.vcpu_create = vmx_vcpu_create,