KVM: TDX: create/free TDX vcpu structure

Implement vcpu related stubs for TDX for create, reset and free.

For now, create only the features that do not require the TDX SEAMCALL.
The TDX specific vcpu initialization will be handled by KVM_TDX_INIT_VCPU.

Signed-off-by: Isaku Yamahata <[e-mail]>
Signed-off-by: Rick Edgecombe <[e-mail]>
---
- Use lapic_in_kernel() (Nikolay Borisov)
Signed-off-by: Paolo Bonzini <[e-mail]>

arch/x86/kvm/vmx/main.c

···
        vmx_vm_destroy(kvm);
 }
 
+static int vt_vcpu_precreate(struct kvm *kvm)
+{
+	if (is_td(kvm))
+		return 0;
+
+	return vmx_vcpu_precreate(kvm);
+}
+
+static int vt_vcpu_create(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return tdx_vcpu_create(vcpu);
+
+	return vmx_vcpu_create(vcpu);
+}
+
+static void vt_vcpu_free(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu)) {
+		tdx_vcpu_free(vcpu);
+		return;
+	}
+
+	vmx_vcpu_free(vcpu);
+}
+
+static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
+{
+	if (is_td_vcpu(vcpu))
+		return;
+
+	vmx_vcpu_reset(vcpu, init_event);
+}
+
 static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 {
 	if (!is_td(kvm))
···
 	.vm_pre_destroy = vt_vm_pre_destroy,
 	.vm_destroy = vt_vm_destroy,
 
-	.vcpu_precreate = vmx_vcpu_precreate,
-	.vcpu_create = vmx_vcpu_create,
-	.vcpu_free = vmx_vcpu_free,
-	.vcpu_reset = vmx_vcpu_reset,
+	.vcpu_precreate = vt_vcpu_precreate,
+	.vcpu_create = vt_vcpu_create,
+	.vcpu_free = vt_vcpu_free,
+	.vcpu_reset = vt_vcpu_reset,
 
 	.prepare_switch_to_guest = vmx_prepare_switch_to_guest,
 	.vcpu_load = vmx_vcpu_load,

arch/x86/kvm/vmx/tdx.c

···
 #include <asm/tdx.h>
 #include "capabilities.h"
 #include "x86_ops.h"
+#include "lapic.h"
 #include "tdx.h"
 
 #pragma GCC poison to_vmx
···
 	kvm_tdx->state = TD_STATE_UNINITIALIZED;
 
 	return 0;
+}
+
+int tdx_vcpu_create(struct kvm_vcpu *vcpu)
+{
+	struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+
+	if (kvm_tdx->state != TD_STATE_INITIALIZED)
+		return -EIO;
+
+	/* TDX module mandates APICv, which requires an in-kernel local APIC. */
+	if (!lapic_in_kernel(vcpu))
+		return -EINVAL;
+
+	fpstate_set_confidential(&vcpu->arch.guest_fpu);
+
+	vcpu->arch.efer = EFER_SCE | EFER_LME | EFER_LMA | EFER_NX;
+
+	vcpu->arch.cr0_guest_owned_bits = -1ul;
+	vcpu->arch.cr4_guest_owned_bits = -1ul;
+
+	/* KVM can't change TSC offset/multiplier as TDX module manages them. */
+	vcpu->arch.guest_tsc_protected = true;
+	vcpu->arch.tsc_offset = kvm_tdx->tsc_offset;
+	vcpu->arch.l1_tsc_offset = vcpu->arch.tsc_offset;
+	vcpu->arch.tsc_scaling_ratio = kvm_tdx->tsc_multiplier;
+	vcpu->arch.l1_tsc_scaling_ratio = kvm_tdx->tsc_multiplier;
+
+	vcpu->arch.guest_state_protected =
+		!(to_kvm_tdx(vcpu->kvm)->attributes & TDX_TD_ATTR_DEBUG);
+
+	if ((kvm_tdx->xfam & XFEATURE_MASK_XTILE) == XFEATURE_MASK_XTILE)
+		vcpu->arch.xfd_no_write_intercept = true;
+
+	return 0;
+}
+
+void tdx_vcpu_free(struct kvm_vcpu *vcpu)
+{
+	/* This is stub for now.  More logic will come. */
 }
 
 static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)

arch/x86/kvm/vmx/x86_ops.h

···
 void tdx_mmu_release_hkid(struct kvm *kvm);
 void tdx_vm_destroy(struct kvm *kvm);
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
+
+int tdx_vcpu_create(struct kvm_vcpu *vcpu);
+void tdx_vcpu_free(struct kvm_vcpu *vcpu);
 #else
 static inline int tdx_vm_init(struct kvm *kvm) { return -EOPNOTSUPP; }
 static inline void tdx_mmu_release_hkid(struct kvm *kvm) {}
 static inline void tdx_vm_destroy(struct kvm *kvm) {}
 static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; }
+
+static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
+static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
 #endif
 
 #endif /* __KVM_X86_VMX_X86_OPS_H */