6.6-stable review patch. If anyone has any objections, please let me know.
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From: Kai Huang kai.huang@intel.com
[ Upstream commit 03a423d40cb30e0e1cb77a801acb56ddb0bf6f5e ]
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: Peter Zijlstra peterz@infradead.org Signed-off-by: Kai Huang kai.huang@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/all/704088f5b4d72c7e24084f7f15bd1ac5005b7213.1692096... Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/coco/tdx/tdcall.S | 3 --- arch/x86/virt/vmx/tdx/tdxcall.S | 29 ++++++++++++++++++++--------- 2 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 2eca5f43734fe..e5d4b7d8ecd4a 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -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)
/* diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S index 49a54356ae992..6bdf6e1379534 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -1,5 +1,6 @@ /* 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 @@ -44,7 +46,7 @@ mov %rsi, %rcx /* Leave input param 2 in RDX */
- .if \host +.if \host seamcall /* * SEAMCALL instruction is essentially a VMExit from VMX root @@ -57,13 +59,10 @@ * 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: - - .else + jc .Lseamcall_vmfailinvalid +.else tdcall - .endif +.endif
/* * Fetch output pointer from stack to R12 (It is used @@ -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