@@ -112,8 +112,12 @@ static inline u64 sc_retry(sc_func_t func, u64 fn,
#define seamcall_saved_ret(_fn, _args) sc_retry(__seamcall_saved_ret, (_fn), (_args))
bool platform_tdx_enabled(void);
+int tdx_cpu_enable(void);
+int tdx_enable(void);
#else
static inline bool platform_tdx_enabled(void) { return false; }
+static inline int tdx_cpu_enable(void) { return -ENODEV; }
+static inline int tdx_enable(void) { return -ENODEV; }
#endif /* CONFIG_INTEL_TDX_HOST */
#endif /* !__ASSEMBLY__ */
@@ -12,14 +12,24 @@
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/printk.h>
+#include <linux/cpu.h>
+#include <linux/spinlock.h>
+#include <linux/percpu-defs.h>
+#include <linux/mutex.h>
#include <asm/msr-index.h>
#include <asm/msr.h>
#include <asm/tdx.h>
+#include "tdx.h"
static u32 tdx_global_keyid __ro_after_init;
static u32 tdx_guest_keyid_start __ro_after_init;
static u32 tdx_nr_guest_keyids __ro_after_init;
+static DEFINE_PER_CPU(bool, tdx_lp_initialized);
+
+static enum tdx_module_status_t tdx_module_status;
+static DEFINE_MUTEX(tdx_module_lock);
+
typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args);
static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *args)
@@ -63,6 +73,163 @@ static inline int sc_retry_prerr(sc_func_t func, sc_err_func_t err_func,
#define seamcall_prerr_ret(__fn, __args) \
sc_retry_prerr(__seamcall_ret, seamcall_err_ret, (__fn), (__args))
+/*
+ * Do the module global initialization once and return its result.
+ * It can be done on any cpu. It's always called with interrupts
+ * disabled.
+ */
+static int try_init_module_global(void)
+{
+ struct tdx_module_args args = {};
+ static DEFINE_RAW_SPINLOCK(sysinit_lock);
+ static bool sysinit_done;
+ static int sysinit_ret;
+
+ lockdep_assert_irqs_disabled();
+
+ raw_spin_lock(&sysinit_lock);
+
+ if (sysinit_done)
+ goto out;
+
+ /* RCX is module attributes and all bits are reserved */
+ args.rcx = 0;
+ sysinit_ret = seamcall_prerr(TDH_SYS_INIT, &args);
+
+ /*
+ * The first SEAMCALL also detects the TDX module, thus
+ * it can fail due to the TDX module is not loaded.
+ * Dump message to let the user know.
+ */
+ if (sysinit_ret == -ENODEV)
+ pr_err("module not loaded\n");
+
+ sysinit_done = true;
+out:
+ raw_spin_unlock(&sysinit_lock);
+ return sysinit_ret;
+}
+
+/**
+ * tdx_cpu_enable - Enable TDX on local cpu
+ *
+ * Do one-time TDX module per-cpu initialization SEAMCALL (and TDX module
+ * global initialization SEAMCALL if not done) on local cpu to make this
+ * cpu be ready to run any other SEAMCALLs.
+ *
+ * Always call this function via IPI function calls.
+ *
+ * Return 0 on success, otherwise errors.
+ */
+int tdx_cpu_enable(void)
+{
+ struct tdx_module_args args = {};
+ int ret;
+
+ if (!platform_tdx_enabled())
+ return -ENODEV;
+
+ lockdep_assert_irqs_disabled();
+
+ if (__this_cpu_read(tdx_lp_initialized))
+ return 0;
+
+ /*
+ * The TDX module global initialization is the very first step
+ * to enable TDX. Need to do it first (if hasn't been done)
+ * before the per-cpu initialization.
+ */
+ ret = try_init_module_global();
+ if (ret)
+ return ret;
+
+ ret = seamcall_prerr(TDH_SYS_LP_INIT, &args);
+ if (ret)
+ return ret;
+
+ __this_cpu_write(tdx_lp_initialized, true);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tdx_cpu_enable);
+
+static int init_tdx_module(void)
+{
+ /*
+ * TODO:
+ *
+ * - Build the list of TDX-usable memory regions.
+ * - Get TDX module "TD Memory Region" (TDMR) global metadata.
+ * - Construct a list of TDMRs to cover all TDX-usable memory
+ * regions.
+ * - Configure the TDMRs and the global KeyID to the TDX module.
+ * - Configure the global KeyID on all packages.
+ * - Initialize all TDMRs.
+ *
+ * Return error before all steps are done.
+ */
+ return -EINVAL;
+}
+
+static int __tdx_enable(void)
+{
+ int ret;
+
+ ret = init_tdx_module();
+ if (ret) {
+ pr_err("module initialization failed (%d)\n", ret);
+ tdx_module_status = TDX_MODULE_ERROR;
+ return ret;
+ }
+
+ pr_info("module initialized\n");
+ tdx_module_status = TDX_MODULE_INITIALIZED;
+
+ return 0;
+}
+
+/**
+ * tdx_enable - Enable TDX module to make it ready to run TDX guests
+ *
+ * This function assumes the caller has: 1) held read lock of CPU hotplug
+ * lock to prevent any new cpu from becoming online; 2) done both VMXON
+ * and tdx_cpu_enable() on all online cpus.
+ *
+ * This function can be called in parallel by multiple callers.
+ *
+ * Return 0 if TDX is enabled successfully, otherwise error.
+ */
+int tdx_enable(void)
+{
+ int ret;
+
+ if (!platform_tdx_enabled())
+ return -ENODEV;
+
+ lockdep_assert_cpus_held();
+
+ mutex_lock(&tdx_module_lock);
+
+ switch (tdx_module_status) {
+ case TDX_MODULE_UNINITIALIZED:
+ ret = __tdx_enable();
+ break;
+ case TDX_MODULE_INITIALIZED:
+ /* Already initialized, great, tell the caller. */
+ ret = 0;
+ break;
+ default:
+ /* Failed to initialize in the previous attempts */
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&tdx_module_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tdx_enable);
+
static int __init record_keyid_partitioning(u32 *tdx_keyid_start,
u32 *nr_tdx_keyids)
{
new file mode 100644
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _X86_VIRT_TDX_H
+#define _X86_VIRT_TDX_H
+
+/*
+ * This file contains both macros and data structures defined by the TDX
+ * architecture and Linux defined software data structures and functions.
+ * The two should not be mixed together for better readability. The
+ * architectural definitions come first.
+ */
+
+/*
+ * TDX module SEAMCALL leaf functions
+ */
+#define TDH_SYS_INIT 33
+#define TDH_SYS_LP_INIT 35
+
+/*
+ * Do not put any hardware-defined TDX structure representations below
+ * this comment!
+ */
+
+/* Kernel defined TDX module status during module initialization. */
+enum tdx_module_status_t {
+ TDX_MODULE_UNINITIALIZED,
+ TDX_MODULE_INITIALIZED,
+ TDX_MODULE_ERROR
+};
+
+#endif