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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>,
	Dexuan Cui <decui@microsoft.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Cc: linux-coco@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	linux-hyperv@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH 20/20] x86/tdx: Remove old TDCALL wrappers
Date: Fri, 17 May 2024 17:19:38 +0300
Message-ID: <20240517141938.4177174-21-kirill.shutemov@linux.intel.com>
In-Reply-To: <20240517141938.4177174-1-kirill.shutemov@linux.intel.com>
References: <20240517141938.4177174-1-kirill.shutemov@linux.intel.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

All code has been converted to new TDCALL wrappers.

Drop the old wrappers.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/boot/compressed/tdx.c    |  6 ----
 arch/x86/coco/tdx/tdcall.S        | 60 ++-----------------------------
 arch/x86/coco/tdx/tdx-shared.c    | 20 -----------
 arch/x86/coco/tdx/tdx.c           | 18 ----------
 arch/x86/include/asm/shared/tdx.h | 43 +---------------------
 arch/x86/virt/vmx/tdx/tdxcall.S   | 29 +++++----------
 tools/objtool/noreturns.h         |  1 -
 7 files changed, 12 insertions(+), 165 deletions(-)

diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c
index 0ae05edc7d42..b74084a46f2f 100644
--- a/arch/x86/boot/compressed/tdx.c
+++ b/arch/x86/boot/compressed/tdx.c
@@ -10,12 +10,6 @@
 
 #include <asm/shared/tdx.h>
 
-/* Called from __tdx_hypercall() for unrecoverable failure */
-void __tdx_hypercall_failed(void)
-{
-	error("TDVMCALL failed. TDX module bug?");
-}
-
 static inline unsigned int tdx_io_in(int size, u16 port)
 {
 	u64 out;
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S
index 5b60b9c8799f..407e2b7ae515 100644
--- a/arch/x86/coco/tdx/tdcall.S
+++ b/arch/x86/coco/tdx/tdcall.S
@@ -1,66 +1,12 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #include <asm/asm-offsets.h>
 #include <asm/asm.h>
+#include <asm/shared/tdx.h>
 
 #include <linux/linkage.h>
-#include <linux/errno.h>
 
-#include "../../virt/vmx/tdx/tdxcall.S"
-
-.section .noinstr.text, "ax"
-
-/*
- * __tdcall()  - Used by TDX guests to request services from the TDX
- * module (does not include VMM services) using TDCALL instruction.
- *
- * __tdcall() function ABI:
- *
- * @fn   (RDI)	- TDCALL Leaf ID, moved to RAX
- * @args (RSI)	- struct tdx_module_args for input
- *
- * Only RCX/RDX/R8-R11 are used as input registers.
- *
- * Return status of TDCALL via RAX.
- */
-SYM_FUNC_START(__tdcall)
-	TDX_MODULE_CALL host=0
-SYM_FUNC_END(__tdcall)
-
-/*
- * __tdcall_ret() - Used by TDX guests to request services from the TDX
- * module (does not include VMM services) using TDCALL instruction, with
- * saving output registers to the 'struct tdx_module_args' used as input.
- *
- * __tdcall_ret() function ABI:
- *
- * @fn   (RDI)	- TDCALL Leaf ID, moved to RAX
- * @args (RSI)	- struct tdx_module_args for input and output
- *
- * Only RCX/RDX/R8-R11 are used as input/output registers.
- *
- * Return status of TDCALL via RAX.
- */
-SYM_FUNC_START(__tdcall_ret)
-	TDX_MODULE_CALL host=0 ret=1
-SYM_FUNC_END(__tdcall_ret)
-
-/*
- * __tdcall_saved_ret() - Used by TDX guests to request services from the
- * TDX module (including VMM services) using TDCALL instruction, with
- * saving output registers to the 'struct tdx_module_args' used as input.
- *
- * __tdcall_saved_ret() function ABI:
- *
- * @fn   (RDI)	- TDCALL leaf ID, moved to RAX
- * @args (RSI)	- struct tdx_module_args for input/output
- *
- * All registers in @args are used as input/output registers.
- *
- * On successful completion, return the hypercall error code.
- */
-SYM_FUNC_START(__tdcall_saved_ret)
-	TDX_MODULE_CALL host=0 ret=1 saved=1
-SYM_FUNC_END(__tdcall_saved_ret)
+/* TDCALL is supported in Binutils >= 2.36 */
+#define tdcall		.byte 0x66,0x0f,0x01,0xcc
 
 /*
  * tdvmcall_trampoline() - Wrapper for TDG.VP.VMCALL. Covers common cases: up
diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c
index 9104e96eeefd..b181f7d4d3b9 100644
--- a/arch/x86/coco/tdx/tdx-shared.c
+++ b/arch/x86/coco/tdx/tdx-shared.c
@@ -69,23 +69,3 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t end)
 
 	return true;
 }
-
-noinstr u64 __tdx_hypercall(struct tdx_module_args *args)
-{
-	/*
-	 * For TDVMCALL explicitly set RCX to the bitmap of shared registers.
-	 * The caller isn't expected to set @args->rcx anyway.
-	 */
-	args->rcx = TDVMCALL_EXPOSE_REGS_MASK;
-
-	/*
-	 * Failure of __tdcall_saved_ret() indicates a failure of the TDVMCALL
-	 * mechanism itself and that something has gone horribly wrong with
-	 * the TDX module.  __tdx_hypercall_failed() never returns.
-	 */
-	if (__tdcall_saved_ret(TDG_VP_VMCALL, args))
-		__tdx_hypercall_failed();
-
-	/* TDVMCALL leaf return code is in R10 */
-	return args->r10;
-}
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 45be53d5eeb4..7d9306bd67af 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -38,13 +38,6 @@
 
 static atomic_long_t nr_shared;
 
-/* Called from __tdx_hypercall() for unrecoverable failure */
-noinstr void __noreturn __tdx_hypercall_failed(void)
-{
-	instrumentation_begin();
-	panic("TDVMCALL failed. TDX module bug?");
-}
-
 #ifdef CONFIG_KVM_GUEST
 long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2,
 		       unsigned long p3, unsigned long p4)
@@ -62,17 +55,6 @@ long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2,
 EXPORT_SYMBOL_GPL(tdx_kvm_hypercall);
 #endif
 
-/*
- * Used for TDX guests to make calls directly to the TD module.  This
- * should only be used for calls that have no legitimate reason to fail
- * or where the kernel can not survive the call failing.
- */
-static inline void tdcall(u64 fn, struct tdx_module_args *args)
-{
-	if (__tdcall_ret(fn, args))
-		panic("TDCALL %lld failed (Buggy TDX module!)\n", fn);
-}
-
 /* Read TD-scoped metadata */
 static inline u64 tdg_vm_rd(u64 field, u64 *value)
 {
diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index 70190ebc63ca..cbbc679d64a2 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h
@@ -55,17 +55,6 @@
 #define TDX_R14		BIT(14)
 #define TDX_R15		BIT(15)
 
-/*
- * These registers are clobbered to hold arguments for each
- * TDVMCALL. They are safe to expose to the VMM.
- * Each bit in this mask represents a register ID. Bit field
- * details can be found in TDX GHCI specification, section
- * titled "TDCALL [TDG.VP.VMCALL] leaf".
- */
-#define TDVMCALL_EXPOSE_REGS_MASK	\
-	(TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8  | TDX_R9  | \
-	 TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15)
-
 /* TDX supported page sizes from the TDX module ABI. */
 #define TDX_PS_4K	0
 #define TDX_PS_2M	1
@@ -193,7 +182,7 @@
 })
 
 /*
- * Used in __tdcall*() to gather the input/output registers' values of the
+ * Used in __seamcall*() to gather the input/output registers' values of the
  * TDCALL instruction when requesting services from the TDX module. This is a
  * software only structure and not part of the TDX module/VMM ABI
  */
@@ -216,36 +205,6 @@ struct tdx_module_args {
 	u64 rsi;
 };
 
-/* Used to communicate with the TDX module */
-u64 __tdcall(u64 fn, struct tdx_module_args *args);
-u64 __tdcall_ret(u64 fn, struct tdx_module_args *args);
-u64 __tdcall_saved_ret(u64 fn, struct tdx_module_args *args);
-
-/* Used to request services from the VMM */
-u64 __tdx_hypercall(struct tdx_module_args *args);
-
-/*
- * Wrapper for standard use of __tdx_hypercall with no output aside from
- * return code.
- */
-static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
-{
-	struct tdx_module_args args = {
-		.r10 = TDX_HYPERCALL_STANDARD,
-		.r11 = fn,
-		.r12 = r12,
-		.r13 = r13,
-		.r14 = r14,
-		.r15 = r15,
-	};
-
-	return __tdx_hypercall(&args);
-}
-
-
-/* Called from __tdx_hypercall() for unrecoverable failure */
-void __noreturn __tdx_hypercall_failed(void);
-
 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end);
 
 /*
diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S
index 016a2a1ec1d6..7ad2fc6ba9c8 100644
--- a/arch/x86/virt/vmx/tdx/tdxcall.S
+++ b/arch/x86/virt/vmx/tdx/tdxcall.S
@@ -4,33 +4,28 @@
 #include <asm/asm.h>
 #include <asm/tdx.h>
 
-/*
- * TDCALL and SEAMCALL are supported in Binutils >= 2.36.
- */
-#define tdcall		.byte 0x66,0x0f,0x01,0xcc
+/* SEAMCALL is supported in Binutils >= 2.36 */
 #define seamcall	.byte 0x66,0x0f,0x01,0xcf
 
 /*
  * TDX_MODULE_CALL - common helper macro for both
  *                 TDCALL and SEAMCALL instructions.
  *
- * TDCALL   - used by TDX guests to make requests to the
- *            TDX module and hypercalls to the VMM.
  * SEAMCALL - used by TDX hosts to make requests to the
  *            TDX module.
  *
  *-------------------------------------------------------------------------
- * TDCALL/SEAMCALL ABI:
+ * SEAMCALL ABI:
  *-------------------------------------------------------------------------
  * Input Registers:
  *
- * RAX                        - TDCALL/SEAMCALL Leaf number.
- * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific input registers.
+ * RAX                        - SEAMCALL Leaf number.
+ * RCX,RDX,RDI,RSI,RBX,R8-R15 - SEAMCALL Leaf specific input registers.
  *
  * Output Registers:
  *
- * RAX                        - TDCALL/SEAMCALL instruction error code.
- * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific output registers.
+ * RAX                        - SEAMCALL instruction error code.
+ * RCX,RDX,RDI,RSI,RBX,R8-R15 - SEAMCALL Leaf specific output registers.
  *
  *-------------------------------------------------------------------------
  *
@@ -42,7 +37,7 @@
  * also tramples on RDI,RSI.  This isn't strictly true, see for example
  * TDH.EXPORT.MEM.
  */
-.macro TDX_MODULE_CALL host:req ret=0 saved=0
+.macro TDX_MODULE_CALL ret=0 saved=0
 	FRAME_BEGIN
 
 	/* Move Leaf ID to RAX */
@@ -85,7 +80,6 @@
 	movq	TDX_MODULE_rsi(%rsi), %rsi
 .endif	/* \saved */
 
-.if \host
 .Lseamcall\@:
 	seamcall
 	/*
@@ -100,9 +94,6 @@
 	 * it is from the Reserved status code class.
 	 */
 	jc .Lseamcall_vmfailinvalid\@
-.else
-	tdcall
-.endif
 
 .if \ret
 .if \saved
@@ -172,11 +163,9 @@
 	xorl %r15d, %r15d
 	xorl %ebx,  %ebx
 	xorl %edi,  %edi
-.endif	/* \ret && \host */
+.endif	/* \saved && \ret */
 
-.if \host
 .Lout\@:
-.endif
 
 .if \saved
 	/* Restore callee-saved GPRs as mandated by the x86_64 ABI */
@@ -190,7 +179,6 @@
 	FRAME_END
 	RET
 
-.if \host
 .Lseamcall_vmfailinvalid\@:
 	mov $TDX_SEAMCALL_VMFAILINVALID, %rax
 	jmp .Lseamcall_fail\@
@@ -215,6 +203,5 @@
 	jmp .Lout\@
 
 	_ASM_EXTABLE_FAULT(.Lseamcall\@, .Lseamcall_trap\@)
-.endif	/* \host */
 
 .endm
diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h
index 0670cacf0734..1e82a96ba960 100644
--- a/tools/objtool/noreturns.h
+++ b/tools/objtool/noreturns.h
@@ -11,7 +11,6 @@ NORETURN(__kunit_abort)
 NORETURN(__module_put_and_kthread_exit)
 NORETURN(__reiserfs_panic)
 NORETURN(__stack_chk_fail)
-NORETURN(__tdx_hypercall_failed)
 NORETURN(__ubsan_handle_builtin_unreachable)
 NORETURN(arch_cpu_idle_dead)
 NORETURN(bch2_trans_in_restart_error)
-- 
2.43.0