[RFC PATCH 58/67] KVM: VMX: Add macro framework to read/write VMCS for VMs and TDs

[isaku . yamahata]

From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>

Add a macro framework to hide VMX vs. TDX details of VMREAD and VMWRITE
so the VMX and TDX can shared common flows, e.g. accessing DTs.

Note, the TDX paths are dead code at this time.  There is no great way
to deal with the chicken-and-egg scenario of having things in place for
TDX without first having TDX.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/kvm/vmx/common.h | 41 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index 58edf1296cbd..baee96abdd7e 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -11,6 +11,47 @@
 #include "vmcs.h"
 #include "vmx.h"
 #include "x86.h"
+#include "tdx.h"
+
+#ifdef CONFIG_KVM_INTEL_TDX
+#define VT_BUILD_VMCS_HELPERS(type, bits, tdbits)			   \
+static __always_inline type vmread##bits(struct kvm_vcpu *vcpu,		   \
+					 unsigned long field)		   \
+{									   \
+	if (unlikely(is_td_vcpu(vcpu))) {				   \
+		if (KVM_BUG_ON(!is_debug_td(vcpu), vcpu->kvm))		   \
+			return 0;					   \
+		return td_vmcs_read##tdbits(to_tdx(vcpu), field);	   \
+	}								   \
+	return vmcs_read##bits(field);					   \
+}									   \
+static __always_inline void vmwrite##bits(struct kvm_vcpu *vcpu,	   \
+					  unsigned long field, type value) \
+{									   \
+	if (unlikely(is_td_vcpu(vcpu))) {				   \
+		if (KVM_BUG_ON(!is_debug_td(vcpu), vcpu->kvm))		   \
+			return;						   \
+		return td_vmcs_write##tdbits(to_tdx(vcpu), field, value);  \
+	}								   \
+	vmcs_write##bits(field, value);					   \
+}
+#else
+#define VT_BUILD_VMCS_HELPERS(type, bits, tdbits)			   \
+static __always_inline type vmread##bits(struct kvm_vcpu *vcpu,		   \
+					 unsigned long field)		   \
+{									   \
+	return vmcs_read##bits(field);					   \
+}									   \
+static __always_inline void vmwrite##bits(struct kvm_vcpu *vcpu,	   \
+					  unsigned long field, type value) \
+{									   \
+	vmcs_write##bits(field, value);					   \
+}
+#endif /* CONFIG_KVM_INTEL_TDX */
+VT_BUILD_VMCS_HELPERS(u16, 16, 16);
+VT_BUILD_VMCS_HELPERS(u32, 32, 32);
+VT_BUILD_VMCS_HELPERS(u64, 64, 64);
+VT_BUILD_VMCS_HELPERS(unsigned long, l, 64);
 
 void vmx_handle_interrupt_nmi_irqoff(struct kvm_vcpu *vcpu, u32 intr_info);
 
-- 
2.17.1