Commit 03a423d4 authored by Kai Huang's avatar Kai Huang Committed by Dave Hansen
Browse files

x86/tdx: Skip saving output regs when SEAMCALL fails with VMFailInvalid 



If SEAMCALL fails with VMFailInvalid, the SEAM software (e.g., the TDX
module) won't have chance to set any output register.  Skip saving the
output registers to the structure in this case.

Also, as '.Lno_output_struct' is the very last symbol before RET, rename
it to '.Lout' to make it short.

Opportunistically make the asm directives unindented.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarKai Huang <kai.huang@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/704088f5b4d72c7e24084f7f15bd1ac5005b7213.1692096753.git.kai.huang%40intel.com
parent 5d092b66

arch/x86/coco/tdx/tdcall.S

+0 −3
Original line number Diff line number Diff line
@@ -78,10 +78,7 @@ 
 * Return status of TDCALL via RAX.

 */

SYM_FUNC_START(__tdx_module_call)

	FRAME_BEGIN

	TDX_MODULE_CALL host=0

	FRAME_END

	RET

SYM_FUNC_END(__tdx_module_call)



/*

arch/x86/virt/vmx/tdx/tdxcall.S

+20 −9
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#include <asm/asm-offsets.h>

#include <asm/frame.h>

#include <asm/tdx.h>



/*
@@ -18,6 +19,7 @@ 
 *            TDX module.

 */

.macro TDX_MODULE_CALL host:req

	FRAME_BEGIN

	/*

	 * R12 will be used as temporary storage for struct tdx_module_output

	 * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL
@@ -57,10 +59,7 @@ 
	 * This value will never be used as actual SEAMCALL error code as

	 * it is from the Reserved status code class.

	 */

	jnc .Lno_vmfailinvalid

	mov $TDX_SEAMCALL_VMFAILINVALID, %rax

.Lno_vmfailinvalid:



	jc .Lseamcall_vmfailinvalid

.else

	tdcall

.endif
@@ -80,7 +79,7 @@ 
	 * Other registers may contain details of the failure.

	 */

	test %r12, %r12

	jz .Lno_output_struct

	jz .Lout



	/* Copy result registers to output struct: */

	movq %rcx, TDX_MODULE_rcx(%r12)
@@ -90,7 +89,19 @@ 
	movq %r10, TDX_MODULE_r10(%r12)

	movq %r11, TDX_MODULE_r11(%r12)



.Lno_output_struct:

.Lout:

	/* Restore the state of R12 register */

	pop %r12



	FRAME_END

	RET



.if \host

.Lseamcall_vmfailinvalid:

	mov $TDX_SEAMCALL_VMFAILINVALID, %rax

	/* pop the unused output pointer back to %r9 */

	pop %r9

	jmp .Lout

.endif	/* \host */



.endm