x86/tdx: Add TDG.MR.KEY.GET ABI support#149
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mingweishih merged 1 commit intoJun 30, 2026
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Pull request overview
Adds TDG.MR.KEY.GET support to the x86 TDX guest stack by exposing a new userspace ioctl and wiring it to a new in-kernel TDCALL wrapper, enabling derivation of a persistent sealing key bound to TD measurements/policy.
Changes:
- Introduces
struct tdx_key_get_reqandTDX_CMD_KEY_GETioctl in the TDX guest UAPI. - Implements
TDX_CMD_KEY_GEThandling in thetdx-guestdriver, including userspace marshalling of TDKEYREQUEST and key output buffers. - Adds the
TDG_MR_KEY_GETleaf ID and atdx_mcall_key_get()wrapper for invoking the TDCALL.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| include/uapi/linux/tdx-guest.h | Adds the KEY.GET ioctl UAPI struct and command definition. |
| drivers/virt/coco/tdx-guest/tdx-guest.c | Adds ioctl handler that allocates/marshals KEY.GET buffers and calls into the TDX module wrapper. |
| arch/x86/include/asm/tdx.h | Declares the new tdx_mcall_key_get() wrapper. |
| arch/x86/include/asm/shared/tdx.h | Adds the TDG.MR.KEY.GET TDCALL leaf ID constant. |
| arch/x86/coco/tdx/tdx.c | Implements tdx_mcall_key_get() wrapper calling __tdcall(). |
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Add support for the TDG.MR.KEY.GET TDCALL, which derives a persistent, hardware-bound sealing key for the TD customized to its measurements and policy. Add the tdx_mcall_key_get() wrapper, the TDX_CMD_KEY_GET ioctl with its tdx_key_get_req UAPI structure, and the tdx_guest driver handler that marshals the TDKEYREQUEST input and key output buffers with the alignment required by the TDX module ABI. [mishih: fix typos and a misplaced apostrophe from the original patch; use _IOWR since the ioctl both reads the request and writes back the key and error code; document that kmalloc()/kzalloc() satisfy the 128B and 32B buffer alignment for these power-of-two sizes; write err_code back on success so callers do not observe a stale value; and use kfree_sensitive() to clear keying material] Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Ming-Wei Shih <mishih@microsoft.com>
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Jun 30, 2026
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Add support for the TDG.MR.KEY.GET TDCALL, which derives a persistent, hardware-bound sealing key for the TD customized to its measurements and policy. Add the tdx_mcall_key_get() wrapper, the TDX_CMD_KEY_GET ioctl with its tdx_key_get_req UAPI structure, and the tdx_guest driver handler that marshals the TDKEYREQUEST input and key output buffers with the alignment required by the TDX module ABI.