[PATCH v2 03/21] x86/virt/tdx: Move low level SEAMCALL helpers out of <asm/tdx.h>

[Chao Gao <chao.gao@intel.com>]

From: Kai Huang <kai.huang@intel.com>

TDX host core code implements three seamcall*() helpers to make SEAMCALL
to the TDX module.  Currently, they are implemented in <asm/tdx.h> and
are exposed to other kernel code which includes <asm/tdx.h>.

However, other than the TDX host core, seamcall*() are not expected to
be used by other kernel code directly.  For instance, for all SEAMCALLs
that are used by KVM, the TDX host core exports a wrapper function for
each of them.

Move seamcall*() and related code out of <asm/tdx.h> and make them only
visible to TDX host core.

Since TDX host core tdx.c is already very heavy, don't put low level
seamcall*() code there but to a new dedicated "seamcall.h".  Also,
currently tdx.c has seamcall_prerr*() helpers which additionally print
error message when calling seamcall*() fails.  Move them to "seamcall.h"
as well.  In such way all low level SEAMCALL helpers are in a dedicated
place, which is much more readable.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Chao Gao <chao.gao@intel.com>
---
v2:
 - new
---
 arch/x86/include/asm/tdx.h       | 24 ----------
 arch/x86/virt/vmx/tdx/seamcall.h | 79 ++++++++++++++++++++++++++++++++
 arch/x86/virt/vmx/tdx/tdx.c      | 46 +------------------
 3 files changed, 80 insertions(+), 69 deletions(-)
 create mode 100644 arch/x86/virt/vmx/tdx/seamcall.h

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index cbea169b5fa0..e872a411a359 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -97,31 +97,7 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
 #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */
 
 #ifdef CONFIG_INTEL_TDX_HOST
-u64 __seamcall(u64 fn, struct tdx_module_args *args);
-u64 __seamcall_ret(u64 fn, struct tdx_module_args *args);
-u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args);
 void tdx_init(void);
-
-#include <asm/archrandom.h>
-
-typedef u64 (*sc_func_t)(u64 fn, struct tdx_module_args *args);
-
-static __always_inline u64 sc_retry(sc_func_t func, u64 fn,
-			   struct tdx_module_args *args)
-{
-	int retry = RDRAND_RETRY_LOOPS;
-	u64 ret;
-
-	do {
-		ret = func(fn, args);
-	} while (ret == TDX_RND_NO_ENTROPY && --retry);
-
-	return ret;
-}
-
-#define seamcall(_fn, _args)		sc_retry(__seamcall, (_fn), (_args))
-#define seamcall_ret(_fn, _args)	sc_retry(__seamcall_ret, (_fn), (_args))
-#define seamcall_saved_ret(_fn, _args)	sc_retry(__seamcall_saved_ret, (_fn), (_args))
 int tdx_enable(void);
 const char *tdx_dump_mce_info(struct mce *m);
 const struct tdx_sys_info *tdx_get_sysinfo(void);
diff --git a/arch/x86/virt/vmx/tdx/seamcall.h b/arch/x86/virt/vmx/tdx/seamcall.h
new file mode 100644
index 000000000000..71b6ffddfa40
--- /dev/null
+++ b/arch/x86/virt/vmx/tdx/seamcall.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2025 Intel Corporation */
+#ifndef _X86_VIRT_SEAMCALL_H
+#define _X86_VIRT_SEAMCALL_H
+
+#include <linux/printk.h>
+#include <linux/types.h>
+#include <asm/archrandom.h>
+#include <asm/tdx.h>
+
+u64 __seamcall(u64 fn, struct tdx_module_args *args);
+u64 __seamcall_ret(u64 fn, struct tdx_module_args *args);
+u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args);
+
+typedef u64 (*sc_func_t)(u64 fn, struct tdx_module_args *args);
+
+static __always_inline u64 sc_retry(sc_func_t func, u64 fn,
+			   struct tdx_module_args *args)
+{
+	int retry = RDRAND_RETRY_LOOPS;
+	u64 ret;
+
+	do {
+		ret = func(fn, args);
+	} while (ret == TDX_RND_NO_ENTROPY && --retry);
+
+	return ret;
+}
+
+#define seamcall(_fn, _args)		sc_retry(__seamcall, (_fn), (_args))
+#define seamcall_ret(_fn, _args)	sc_retry(__seamcall_ret, (_fn), (_args))
+#define seamcall_saved_ret(_fn, _args)	sc_retry(__seamcall_saved_ret, (_fn), (_args))
+
+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)
+{
+	pr_err("SEAMCALL (%llu) failed: %#016llx\n", fn, err);
+}
+
+static inline void seamcall_err_ret(u64 fn, u64 err,
+				    struct tdx_module_args *args)
+{
+	seamcall_err(fn, err, args);
+	pr_err("RCX %#016llx RDX %#016llx R08 %#016llx\n",
+			args->rcx, args->rdx, args->r8);
+	pr_err("R09 %#016llx R10 %#016llx R11 %#016llx\n",
+			args->r9, args->r10, args->r11);
+}
+
+static __always_inline int sc_retry_prerr(sc_func_t func,
+					  sc_err_func_t err_func,
+					  u64 fn, struct tdx_module_args *args)
+{
+	u64 sret = sc_retry(func, fn, args);
+
+	if (sret == TDX_SUCCESS)
+		return 0;
+
+	if (sret == TDX_SEAMCALL_VMFAILINVALID)
+		return -ENODEV;
+
+	if (sret == TDX_SEAMCALL_GP)
+		return -EOPNOTSUPP;
+
+	if (sret == TDX_SEAMCALL_UD)
+		return -EACCES;
+
+	err_func(fn, sret, args);
+	return -EIO;
+}
+
+#define seamcall_prerr(__fn, __args)						\
+	sc_retry_prerr(__seamcall, seamcall_err, (__fn), (__args))
+
+#define seamcall_prerr_ret(__fn, __args)					\
+	sc_retry_prerr(__seamcall_ret, seamcall_err_ret, (__fn), (__args))
+
+#endif
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index f429a5fdced2..b367bb1d94ed 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -38,6 +38,7 @@
 #include <asm/cpu_device_id.h>
 #include <asm/processor.h>
 #include <asm/mce.h>
+#include "seamcall.h"
 #include "tdx.h"
 
 static u32 tdx_global_keyid __ro_after_init;
@@ -58,51 +59,6 @@ static LIST_HEAD(tdx_memlist);
 
 static struct tdx_sys_info tdx_sysinfo;
 
-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)
-{
-	pr_err("SEAMCALL (%llu) failed: %#016llx\n", fn, err);
-}
-
-static inline void seamcall_err_ret(u64 fn, u64 err,
-				    struct tdx_module_args *args)
-{
-	seamcall_err(fn, err, args);
-	pr_err("RCX %#016llx RDX %#016llx R08 %#016llx\n",
-			args->rcx, args->rdx, args->r8);
-	pr_err("R09 %#016llx R10 %#016llx R11 %#016llx\n",
-			args->r9, args->r10, args->r11);
-}
-
-static __always_inline int sc_retry_prerr(sc_func_t func,
-					  sc_err_func_t err_func,
-					  u64 fn, struct tdx_module_args *args)
-{
-	u64 sret = sc_retry(func, fn, args);
-
-	if (sret == TDX_SUCCESS)
-		return 0;
-
-	if (sret == TDX_SEAMCALL_VMFAILINVALID)
-		return -ENODEV;
-
-	if (sret == TDX_SEAMCALL_GP)
-		return -EOPNOTSUPP;
-
-	if (sret == TDX_SEAMCALL_UD)
-		return -EACCES;
-
-	err_func(fn, sret, args);
-	return -EIO;
-}
-
-#define seamcall_prerr(__fn, __args)						\
-	sc_retry_prerr(__seamcall, seamcall_err, (__fn), (__args))
-
-#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
-- 
2.47.3