KVM: TDX: Add helper function to initialize TDX module

Add two helper function to initialize TDX module and get system-wide
parameters.  When TDX module is needed, dynamically initialize the TDX
module.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>

arch/x86/kvm/vmx/main.c

@@ -5,6 +5,7 @@
 #include "vmx.h"
 #include "nested.h"
 #include "pmu.h"
+#include "tdx.h"
 
 #ifdef CONFIG_INTEL_TDX_HOST
 static bool __read_mostly enable_tdx = true;
@@ -32,6 +33,31 @@ static __init int vt_hardware_setup(void)
 	return 0;
 }
 
+int tdx_enable(void)
+{
+	static DEFINE_MUTEX(tdx_init_lock);
+	static bool __read_mostly tdx_module_initialized;
+	int ret = 0;
+
+	mutex_lock(&tdx_init_lock);
+	if (!enable_tdx) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (!tdx_module_initialized) {
+		ret = tdx_module_setup();
+		if (!ret)
+			tdx_module_initialized = true;
+		else
+			disable_tdx();
+	}
+
+out:
+	mutex_unlock(&tdx_init_lock);
+	return ret;
+}
+
 struct kvm_x86_ops vt_x86_ops __initdata = {
 	.name = "kvm_intel",
 

arch/x86/kvm/vmx/tdx.c

@@ -34,9 +34,56 @@ static void __init tdx_keyids_init(void)
 	tdx_seam_keyid = tdx_keyids_start;
 }
 
+/* Capabilities of KVM + the TDX module. */
+struct tdx_capabilities tdx_caps;
+
 static u64 hkid_mask __ro_after_init;
 static u8 hkid_start_pos __ro_after_init;
 
+int tdx_module_setup(void)
+{
+	struct tdsysinfo_struct *tdsysinfo;
+	int ret = 0;
+
+	BUILD_BUG_ON(sizeof(*tdsysinfo) != 1024);
+	BUILD_BUG_ON(TDX_MAX_NR_CPUID_CONFIGS != 37);
+
+	tdsysinfo = kmalloc(sizeof(*tdsysinfo), GFP_KERNEL);
+	if (!tdsysinfo)
+		return -ENOMEM;
+
+	ret = init_tdx(tdsysinfo);
+	if (ret) {
+		pr_info("Failed to initialize TDX module.\n");
+		goto out;
+	}
+
+	tdx_caps.tdcs_nr_pages = tdsysinfo->tdcs_base_size / PAGE_SIZE;
+	tdx_caps.tdvpx_nr_pages = tdsysinfo->tdvps_base_size / PAGE_SIZE - 1;
+
+	tdx_caps.attrs_fixed0 = tdsysinfo->attributes_fixed0;
+	tdx_caps.attrs_fixed1 = tdsysinfo->attributes_fixed1;
+	tdx_caps.xfam_fixed0 =	tdsysinfo->xfam_fixed0;
+	tdx_caps.xfam_fixed1 = tdsysinfo->xfam_fixed1;
+
+	tdx_caps.nr_cpuid_configs = tdsysinfo->num_cpuid_config;
+	if (tdx_caps.nr_cpuid_configs > TDX_MAX_NR_CPUID_CONFIGS) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (!memcpy(tdx_caps.cpuid_configs, tdsysinfo->cpuid_configs,
+			tdsysinfo->num_cpuid_config *
+			sizeof(struct tdx_cpuid_config))) {
+		ret = -EIO;
+		goto out;
+	}
+
+out:
+	kfree(tdsysinfo);
+	return ret;
+}
+
 int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
 {
 	u32 max_pa;

arch/x86/kvm/vmx/tdx.h

@@ -10,6 +10,8 @@
 #include "tdx_ops.h"
 
 #ifdef CONFIG_INTEL_TDX_HOST
+int tdx_module_setup(void);
+int tdx_enable(void);
 
 struct tdx_td_page {
 	unsigned long va;
@@ -31,6 +33,24 @@ struct vcpu_tdx {
 	struct tdx_td_page *tdvpx;
 };
 
+#define TDX_MAX_NR_CPUID_CONFIGS					\
+	((sizeof(struct tdsysinfo_struct) -				\
+		offsetof(struct tdsysinfo_struct, cpuid_configs))	\
+		/ sizeof(struct tdx_cpuid_config))
+
+struct tdx_capabilities {
+	u8 tdcs_nr_pages;
+	u8 tdvpx_nr_pages;
+
+	u64 attrs_fixed0;
+	u64 attrs_fixed1;
+	u64 xfam_fixed0;
+	u64 xfam_fixed1;
+
+	u32 nr_cpuid_configs;
+	struct tdx_cpuid_config cpuid_configs[TDX_MAX_NR_CPUID_CONFIGS];
+};
+
 static inline bool is_td(struct kvm *kvm)
 {
 	return kvm->arch.vm_type == KVM_X86_TDX_VM;
@@ -137,6 +157,8 @@ TDX_BUILD_TDVPS_ACCESSORS(64, STATE_NON_ARCH, state_non_arch);
 TDX_BUILD_TDVPS_ACCESSORS(8, MANAGEMENT, management);
 
 #else
+static inline int tdx_module_setup(void) { return -EOPNOTSUPP; };
+
 struct kvm_tdx;
 struct vcpu_tdx;
 

arch/x86/kvm/vmx/tdx_arch.h

@@ -6,6 +6,62 @@
 
 #include <linux/types.h>
 
+/*
+ * workaround to compile.
+ * TODO: once the TDX module initiation code in x86 host is merged, remove this.
+ * The function returns struct tdsysinfo_struct from TDX module provides which
+ * is the system wide information about the TDX module.
+ * Return NULL if the TDX module is not ready for KVM to use for TDX VM guest
+ * life cycle.
+ */
+#if __has_include(<asm/tdx_host.h>)
+#include <asm/tdx_host.h>
+#else
+struct tdx_cpuid_config {
+	u32 leaf;
+	u32 sub_leaf;
+	u32 eax;
+	u32 ebx;
+	u32 ecx;
+	u32 edx;
+} __packed;
+
+struct tdsysinfo_struct {
+	/* The TDX Module Info */
+	u32 attributes;
+	u32 vendor_id;
+	u32 build_date;
+	u16 build_num;
+	u16 minor_version;
+	u16 major_version;
+	u8 reserved0[14];
+	/* Memory Info */
+	u16 max_tdmrs;
+	u16 max_reserved_per_tdmr;
+	u16 pamt_entry_size;
+	u8 reserved1[10];
+	/* Control Struct Info */
+	u16 tdcs_base_size;
+	u8 reserved2[2];
+	u16 tdvps_base_size;
+	u8 tdvps_xfam_dependent_size;
+	u8 reserved3[9];
+	/* TD Capabilities */
+	u64 attributes_fixed0;
+	u64 attributes_fixed1;
+	u64 xfam_fixed0;
+	u64 xfam_fixed1;
+	u8 reserved4[32];
+	u32 num_cpuid_config;
+	union {
+		struct tdx_cpuid_config cpuid_configs[0];
+		u8 reserved5[892];
+	};
+} __packed __aligned(1024);
+
+static inline int init_tdx(struct tdsysinfo_struct *tdsysinfo) { return -ENODEV; }
+#endif
+
 /*
  * TDX SEAMCALL API function leaves
  */

arch/x86/kvm/vmx/tdx_stubs.c

@@ -6,4 +6,5 @@
 void __init tdx_pre_kvm_init(unsigned int *vcpu_size,
 			unsigned int *vcpu_align, unsigned int *vm_size) {}
 
+int tdx_module_setup(void) { return -EOPNOTSUPP; };
 int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; }