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

[Xiaoyao Li]

On 9/24/2026 12:10 PM, 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.

I think it needs to be split into 2 patches:
- implement tdx_tdcm_* and justify why poll mode in chosen instread of notification.

- Add TDCM_OP_CHECK_TEEIO_SUPP check to tdx_devsec_lock(). We need explain what
it does, why we need it, and why it needs to be in tdx_devsec_lock() as the
first step.

> 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,

why not naming them TDCM_xxx_ERROR as GHCI definitions?

TDCM_ERROR_TDX_MODULE reads like lacking some information at the end. For
example, it can be TDCM_ERROR_TDX_MODULE_DURING_UPDATE.

> +};
> +
> +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[];

since data is not used in tdx_is_dev_teeio_support(), is it really needed?

> +} __packed;
> +
> +#define MAX_TDI_REPORT_SIZE	(16 * PAGE_SIZE)

Add some info in the changelog of where the 16 comes?

>  u64 tdx_hcall_tdcm(u16 devid, void *buf, size_t size, u8 vector);
>  int tdx_mcall_tdi_read(u64 func_id, u64 field, u64 *value);
>  #endif
> diff --git a/drivers/virt/coco/tdx-guest/connect.c b/drivers/virt/coco/tdx-guest/connect.c
> index 80ae7c19e179..1f52a187b30f 100644
> --- a/drivers/virt/coco/tdx-guest/connect.c
> +++ b/drivers/virt/coco/tdx-guest/connect.c
> @@ -7,13 +7,127 @@
>  
>  #define pr_fmt(fmt)		KBUILD_MODNAME ": tdx_connect: " fmt
>  
> +#include <linux/iopoll.h>
>  #include <linux/pci.h>
>  #include <linux/pci-tsm.h>
> +#include <linux/set_memory.h>
>  #include <linux/tsm.h>
>  #include <asm/tdx.h>
>  
>  #include "tdx-guest.h"
>  
> +/**
> + * struct tdcm_ctx - TEE-IO Device Configuration and Management (TDCM) context
> + * @buf: Pointer to 4KB-aligned shared memory (>= one page) used as the command
> + *       buffer on input and the response buffer on output.
> + * @buf_size: Total size of the shared memory buffer.
> + * @max_rsp_data_sz: Maximum expected size of the response data.
> + * @rsp_data_sz: Actual size of the response data populated by the VMM.
> + * @devid: Device Identifier.

As I commented in patch 3, can we add more info of devid. What is it supposed to be?