[RFC PATCH 01/15] x86/tdx: Export tdg_vm_rd() for tdx-guest module
From: Zhenzhong Duan <hidden>
Date: 2026-09-24 04:10:50
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Export tdg_vm_rd() to allow the tdx-guest driver module to directly read TD-scoped metadata fields from the Trust Domain Control Structure (TDCS) via TDG.VM.RD TDCALL. Since tdg_vm_rd() is read-only and cannot cause harm, exporting it directly is simpler and more flexible. This allows the tdx-guest driver to read any TDCS field it needs. In a following patch, the tdx-guest driver will use tdg_vm_rd() to read TDCS_CONFIG_FLAGS field directly. Signed-off-by: Zhenzhong Duan <redacted> --- arch/x86/coco/tdx/tdx.c | 3 ++- arch/x86/include/asm/tdx.h | 2 ++ 2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index f904a636d449..22cc177a6db4 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c@@ -79,7 +79,7 @@ static inline void tdcall(u64 fn, struct tdx_module_args *args) } /* Read TD-scoped metadata */ -static inline u64 tdg_vm_rd(u64 field, u64 *value) +u64 tdg_vm_rd(u64 field, u64 *value) { struct tdx_module_args args = { .rdx = field,
@@ -91,6 +91,7 @@ static inline u64 tdg_vm_rd(u64 field, u64 *value) return ret; } +EXPORT_SYMBOL_FOR_MODULES(tdg_vm_rd, "tdx-guest"); /* Write TD-scoped metadata */ static inline u64 tdg_vm_wr(u64 field, u64 value, u64 mask)
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 89e97d5761d8..884bb8067521 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h@@ -77,6 +77,8 @@ void tdx_halt(void); bool tdx_early_handle_ve(struct pt_regs *regs); +u64 tdg_vm_rd(u64 field, u64 *value); + int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport); int tdx_mcall_extend_rtmr(u8 index, u8 *data);
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2.52.0