KVM: TDX: Stub in tdx.h with structs, accessors, and VMCS helpers

Stub in kvm_tdx, vcpu_tdx, their various accessors, and VMCS helpers.
The VMCS helpers, which rely on the stubs, will be used by preparatory
patches to move VMX functions for accessing VMCS state to common code.

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

arch/x86/kvm/Makefile

@@ -29,7 +29,10 @@ kvm-$(CONFIG_KVM_XEN)	+= xen.o
 kvm-intel-y		+= vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
 			   vmx/evmcs.o vmx/nested.o vmx/posted_intr.o vmx/main.o
 kvm-intel-$(CONFIG_X86_SGX_KVM)	+= vmx/sgx.o
-kvm-intel-$(CONFIG_INTEL_TDX_HOST)	+= vmx/tdx_error.o
+kvm-intel-$(CONFIG_INTEL_TDX_HOST)	+= vmx/tdx_error.o vmx/tdx.o
+ifneq ($(CONFIG_INTEL_TDX_HOST),y)
+kvm-intel-y				+= vmx/tdx_stubs.o
+endif
 
 kvm-amd-y		+= svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o svm/sev.o
 

arch/x86/kvm/vmx/main.c

@@ -164,6 +164,9 @@ static int __init vt_init(void)
 	unsigned int vcpu_size = 0, vcpu_align = 0;
 	int r;
 
+	/* tdx_pre_kvm_init must be called before vmx_pre_kvm_init(). */
+	tdx_pre_kvm_init(&vcpu_size, &vcpu_align, &vt_x86_ops.vm_size);
+
 	vmx_pre_kvm_init(&vcpu_size, &vcpu_align);
 
 	r = kvm_init(&vt_init_ops, vcpu_size, vcpu_align, THIS_MODULE);

arch/x86/kvm/vmx/tdx.c

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cpu.h>
+#include <linux/kvm_host.h>
+
+#include "tdx_errno.h"
+#include "tdx_ops.h"
+#include "x86_ops.h"
+#include "tdx.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "tdx: " fmt
+
+void __init tdx_pre_kvm_init(unsigned int *vcpu_size,
+			unsigned int *vcpu_align, unsigned int *vm_size)
+{
+	*vcpu_size = sizeof(struct vcpu_tdx);
+	*vcpu_align = __alignof__(struct vcpu_tdx);
+
+	if (sizeof(struct kvm_tdx) > *vm_size)
+		*vm_size = sizeof(struct kvm_tdx);
+}

arch/x86/kvm/vmx/tdx.h

@@ -0,0 +1,156 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_TDX_H
+#define __KVM_X86_TDX_H
+
+#include <linux/list.h>
+#include <linux/kvm_host.h>
+
+#include "tdx_errno.h"
+#include "tdx_arch.h"
+#include "tdx_ops.h"
+
+#ifdef CONFIG_INTEL_TDX_HOST
+
+struct tdx_td_page {
+	unsigned long va;
+	hpa_t pa;
+	bool added;
+};
+
+struct kvm_tdx {
+	struct kvm kvm;
+
+	struct tdx_td_page tdr;
+	struct tdx_td_page *tdcs;
+};
+
+struct vcpu_tdx {
+	struct kvm_vcpu	vcpu;
+
+	struct tdx_td_page tdvpr;
+	struct tdx_td_page *tdvpx;
+};
+
+static inline bool is_td(struct kvm *kvm)
+{
+	return kvm->arch.vm_type == KVM_X86_TDX_VM;
+}
+
+static inline bool is_td_vcpu(struct kvm_vcpu *vcpu)
+{
+	return is_td(vcpu->kvm);
+}
+
+static inline bool is_debug_td(struct kvm_vcpu *vcpu)
+{
+	return !vcpu->arch.guest_state_protected;
+}
+
+static inline struct kvm_tdx *to_kvm_tdx(struct kvm *kvm)
+{
+	return container_of(kvm, struct kvm_tdx, kvm);
+}
+
+static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu)
+{
+	return container_of(vcpu, struct vcpu_tdx, vcpu);
+}
+
+static __always_inline void tdvps_vmcs_check(u32 field, u8 bits)
+{
+	BUILD_BUG_ON_MSG(__builtin_constant_p(field) && (field) & 0x1,
+			 "Read/Write to TD VMCS *_HIGH fields not supported");
+
+	BUILD_BUG_ON(bits != 16 && bits != 32 && bits != 64);
+
+	BUILD_BUG_ON_MSG(bits != 64 && __builtin_constant_p(field) &&
+			 (((field) & 0x6000) == 0x2000 ||
+			  ((field) & 0x6000) == 0x6000),
+			 "Invalid TD VMCS access for 64-bit field");
+	BUILD_BUG_ON_MSG(bits != 32 && __builtin_constant_p(field) &&
+			 ((field) & 0x6000) == 0x4000,
+			 "Invalid TD VMCS access for 32-bit field");
+	BUILD_BUG_ON_MSG(bits != 16 && __builtin_constant_p(field) &&
+			 ((field) & 0x6000) == 0x0000,
+			 "Invalid TD VMCS access for 16-bit field");
+}
+
+static __always_inline void tdvps_state_non_arch_check(u64 field, u8 bits) {}
+static __always_inline void tdvps_management_check(u64 field, u8 bits) {}
+
+#define TDX_BUILD_TDVPS_ACCESSORS(bits, uclass, lclass)				\
+static __always_inline u##bits td_##lclass##_read##bits(struct vcpu_tdx *tdx,	\
+							u32 field)		\
+{										\
+	struct tdx_ex_ret ex_ret;						\
+	u64 err;								\
+										\
+	tdvps_##lclass##_check(field, bits);					\
+	err = tdh_vp_rd(tdx->tdvpr.pa, TDVPS_##uclass(field), &ex_ret);		\
+	if (unlikely(err)) {							\
+		pr_err("TDH_VP_RD["#uclass".0x%x] failed: 0x%llx\n",		\
+		       field, err);						\
+		return 0;							\
+	}									\
+	return (u##bits)ex_ret.r8;						\
+}										\
+static __always_inline void td_##lclass##_write##bits(struct vcpu_tdx *tdx,	\
+						      u32 field, u##bits val)	\
+{										\
+	struct tdx_ex_ret ex_ret;						\
+	u64 err;								\
+										\
+	tdvps_##lclass##_check(field, bits);					\
+	err = tdh_vp_wr(tdx->tdvpr.pa, TDVPS_##uclass(field), val,		\
+		      GENMASK_ULL(bits - 1, 0), &ex_ret);			\
+	if (unlikely(err))							\
+		pr_err("TDH_VP_WR["#uclass".0x%x] = 0x%llx failed: 0x%llx\n",	\
+		       field, (u64)val, err);					\
+}										\
+static __always_inline void td_##lclass##_setbit##bits(struct vcpu_tdx *tdx,	\
+						       u32 field, u64 bit)	\
+{										\
+	struct tdx_ex_ret ex_ret;						\
+	u64 err;								\
+										\
+	tdvps_##lclass##_check(field, bits);					\
+	err = tdh_vp_wr(tdx->tdvpr.pa, TDVPS_##uclass(field), bit, bit,		\
+			&ex_ret);						\
+	if (unlikely(err))							\
+		pr_err("TDH_VP_WR["#uclass".0x%x] |= 0x%llx failed: 0x%llx\n",	\
+		       field, bit, err);					\
+}										\
+static __always_inline void td_##lclass##_clearbit##bits(struct vcpu_tdx *tdx,	\
+							 u32 field, u64 bit)	\
+{										\
+	struct tdx_ex_ret ex_ret;						\
+	u64 err;								\
+										\
+	tdvps_##lclass##_check(field, bits);					\
+	err = tdh_vp_wr(tdx->tdvpr.pa, TDVPS_##uclass(field), 0, bit,		\
+			&ex_ret);						\
+	if (unlikely(err))							\
+		pr_err("TDH_VP_WR["#uclass".0x%x] &= ~0x%llx failed: 0x%llx\n",	\
+		       field, bit,  err);					\
+}
+
+TDX_BUILD_TDVPS_ACCESSORS(16, VMCS, vmcs);
+TDX_BUILD_TDVPS_ACCESSORS(32, VMCS, vmcs);
+TDX_BUILD_TDVPS_ACCESSORS(64, VMCS, vmcs);
+
+TDX_BUILD_TDVPS_ACCESSORS(64, STATE_NON_ARCH, state_non_arch);
+TDX_BUILD_TDVPS_ACCESSORS(8, MANAGEMENT, management);
+
+#else
+struct kvm_tdx;
+struct vcpu_tdx;
+
+static inline bool is_td(struct kvm *kvm) { return false; }
+static inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }
+static inline bool is_debug_td(struct kvm_vcpu *vcpu) { return false; }
+static inline struct kvm_tdx *to_kvm_tdx(struct kvm *kvm) { return NULL; }
+static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu) { return NULL; }
+
+#endif /* CONFIG_INTEL_TDX_HOST */
+
+#endif /* __KVM_X86_TDX_H */

arch/x86/kvm/vmx/tdx_stubs.c

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kvm_host.h>
+
+void __init tdx_pre_kvm_init(unsigned int *vcpu_size,
+			unsigned int *vcpu_align, unsigned int *vm_size) {}

arch/x86/kvm/vmx/x86_ops.h

@@ -123,4 +123,7 @@ void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu);
 #endif
 void vmx_setup_mce(struct kvm_vcpu *vcpu);
 
+void __init tdx_pre_kvm_init(unsigned int *vcpu_size,
+			unsigned int *vcpu_align, unsigned int *vm_size);
+
 #endif /* __KVM_X86_VMX_X86_OPS_H */