RE: [RFC PATCH 05/15] virt: tdx-guest: Add TDCM helpers and TEE-IO support check

[Duan, Zhenzhong]

>-----Original Message-----
>From: Nikolay Borisov <nik.borisov@xxxxxxxx>
>Subject: Re: [RFC PATCH 05/15] virt: tdx-guest: Add TDCM helpers and TEE-IO
>support check
>
>
>
>On 24.09.26 г. 7:10 ч., Zhenzhong Duan wrote:
>> Implement internal helper wrappers tdx_tdcm_alloc(), tdx_tdcm_run(),
>> and tdx_tdcm_free() to manage execution context lifecycle for TDX Connect
>> TEE-IO Device Control and Management (TDCM) commands.
>>
>> Use these infrastructures to deploy all TDCM commands to orchestrate
>> trusted device management, beginning with the first command,
>> TDCM_OP_CHECK_TEEIO_SUPP, executed during the secure device locking
>> sequence.
>>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx>
>> ---
>>   arch/x86/include/asm/tdx.h            |  48 +++++++++
>>   drivers/virt/coco/tdx-guest/connect.c | 139 ++++++++++++++++++++++++++
>>   2 files changed, 187 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
>> index 4937e23d5483..71cd701d346f 100644
>> --- a/arch/x86/include/asm/tdx.h
>> +++ b/arch/x86/include/asm/tdx.h
>> @@ -105,6 +105,54 @@ int tdx_mcall_extend_rtmr(u8 index, u8 *data);
>>   u64 tdx_hcall_get_quote(u8 *buf, size_t size);
>>
>>   #ifdef CONFIG_TDX_CONNECT_GUEST
>> +enum tdcm_operation {
>> +	TDCM_OP_CHECK_TEEIO_SUPP	= 1,
>> +	TDCM_OP_BIND			= 2,
>> +	TDCM_OP_GET_DEV_INFO		= 3,
>> +	TDCM_OP_GET_TDI_REPORT		= 4,
>> +	TDCM_OP_START_TDI		= 5,
>> +	TDCM_OP_GET_TDI_STATE		= 6,
>> +	TDCM_OP_UNBIND			= 7,
>> +};
>> +
>> +enum tdcm_status {
>> +	TDCM_STATUS_WAIT		= 0,
>> +	TDCM_STATUS_COMPLETED		= 1,
>> +	TDCM_STATUS_ERROR		= 2,
>> +};
>> +
>> +enum tdcm_error {
>> +	TDCM_ERROR_TDX_MODULE		= 10,
>> +	TDCM_ERROR_TDXIO_DEVICE		= 11,
>> +	TDCM_ERROR_SPDM_MESSAGE		= 12,
>> +	TDCM_ERROR_IDE_KM_MESSAGE	= 13,
>> +	TDCM_ERROR_TDISP_MESSAGE	= 14,
>> +	TDCM_ERROR_INVALID_STATE	= 15,
>> +};
>> +
>> +struct tdvmcall_tdcm {
>> +	__u16 operation;  /* See enum tdcm_operation */
>> +	__u8  version;
>> +	__u8  rsvd0;
>> +	__u32 rsvd1;
>> +
>> +	__u8  status;     /* See enum tdcm_status */
>> +	__u8  error;      /* See enum tdcm_error */
>> +	__u16 rsvd2;
>> +	__u32 rsvd3;
>> +
>> +	__u32 data_length;
>> +
>> +	__u8  data[];
>> +} __packed;
>> +
>> +struct tdcm_rsp_check_teeio_supp {
>> +	__u8 is_supported;
>> +	__u8  data[];
>> +} __packed;
>> +
>> +#define MAX_TDI_REPORT_SIZE	(16 * PAGE_SIZE)
>
>Since TDCM and all concepts around it are coupled to TDX Connect why are
>those defines in the shared tdx.h file? OTOH, why is struct tdcm_ctx {}
>defined in connect.c and not in the shared file? I think it's high time
>we decided whether code coming for additional functionality should go
>into the shared header or a file, specific to said functionality.
>
>My 2 cents are that since TDCM is solely related to connect then it
>should probably be part of connect.h or some private header under
>tdx-guest/ directory. It's not expected for kernel proper to use that
>interface, no ?

Fair point, thanks for suggesting.

I’ll move the TDCM enums, command/response structures, and related
constants into connect.c for now. 

If they need to be shared by multiple TDX Connect source files in 
later patches, I’ll introduce a private header under 
drivers/virt/coco/tdx-guest/