Re: [PATCH v8 008/103] x86/virt/tdx: Add a helper function to return system wide info about TDX module

[Yuan Yao]

On Sun, Aug 07, 2022 at 03:00:53PM -0700, isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> TDX KVM needs system-wide information about the TDX module, struct
> tdsysinfo_struct.  Add a helper function tdx_get_sysinfo() to return it
> instead of KVM getting it with various error checks.  Move out the struct
> definition about it to common place arch/x86/include/asm/tdx.h.

Will this be one of TDX's host patch set? The changes for
arch/x86/include/asm/tdx.h looks like exposing some struct definitaion
as part of API to user of TDX (now it's KVM).

>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
>  arch/x86/include/asm/tdx.h  | 55 +++++++++++++++++++++++++++++++++++++
>  arch/x86/virt/vmx/tdx/tdx.c | 20 +++++++++++---
>  arch/x86/virt/vmx/tdx/tdx.h | 52 -----------------------------------
>  3 files changed, 71 insertions(+), 56 deletions(-)
>
> diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
> index 801f6e10b2db..dfea0dd71bc1 100644
> --- a/arch/x86/include/asm/tdx.h
> +++ b/arch/x86/include/asm/tdx.h
> @@ -89,11 +89,66 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
>  #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */
>
>  #ifdef CONFIG_INTEL_TDX_HOST
> +struct tdx_cpuid_config {
> +	u32	leaf;
> +	u32	sub_leaf;
> +	u32	eax;
> +	u32	ebx;
> +	u32	ecx;
> +	u32	edx;
> +} __packed;
> +
> +#define TDSYSINFO_STRUCT_SIZE		1024
> +#define TDSYSINFO_STRUCT_ALIGNMENT	1024
> +
> +struct tdsysinfo_struct {
> +	/* TDX-SEAM Module Info */
> +	u32	attributes;
> +	u32	vendor_id;
> +	u32	build_date;
> +	u16	build_num;
> +	u16	minor_version;
> +	u16	major_version;
> +	u8	reserved0[14];
> +	/* Memory Info */
> +	u16	max_tdmrs;
> +	u16	max_reserved_per_tdmr;
> +	u16	pamt_entry_size;
> +	u8	reserved1[10];
> +	/* Control Struct Info */
> +	u16	tdcs_base_size;
> +	u8	reserved2[2];
> +	u16	tdvps_base_size;
> +	u8	tdvps_xfam_dependent_size;
> +	u8	reserved3[9];
> +	/* TD Capabilities */
> +	u64	attributes_fixed0;
> +	u64	attributes_fixed1;
> +	u64	xfam_fixed0;
> +	u64	xfam_fixed1;
> +	u8	reserved4[32];
> +	u32	num_cpuid_config;
> +	/*
> +	 * The actual number of CPUID_CONFIG depends on above
> +	 * 'num_cpuid_config'.  The size of 'struct tdsysinfo_struct'
> +	 * is 1024B defined by TDX architecture.  Use a union with
> +	 * specific padding to make 'sizeof(struct tdsysinfo_struct)'
> +	 * equal to 1024.
> +	 */
> +	union {
> +		struct tdx_cpuid_config	cpuid_configs[0];
> +		u8			reserved5[892];
> +	};
> +} __packed __aligned(TDSYSINFO_STRUCT_ALIGNMENT);
> +
>  bool platform_tdx_enabled(void);
>  int tdx_init(void);
> +const struct tdsysinfo_struct *tdx_get_sysinfo(void);
>  #else	/* !CONFIG_INTEL_TDX_HOST */
>  static inline bool platform_tdx_enabled(void) { return false; }
>  static inline int tdx_init(void)  { return -ENODEV; }
> +struct tdsysinfo_struct;
> +static inline const struct tdsysinfo_struct *tdx_get_sysinfo(void) { return NULL; }
>  #endif	/* CONFIG_INTEL_TDX_HOST */
>
>  #endif /* !__ASSEMBLY__ */
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index 787b26de8f53..b9567a2217df 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -354,9 +354,9 @@ static int check_cmrs(struct cmr_info *cmr_array, int *actual_cmr_num)
>  	return 0;
>  }
>
> -static int tdx_get_sysinfo(struct tdsysinfo_struct *tdsysinfo,
> -			   struct cmr_info *cmr_array,
> -			   int *actual_cmr_num)
> +static int __tdx_get_sysinfo(struct tdsysinfo_struct *tdsysinfo,
> +			     struct cmr_info *cmr_array,
> +			     int *actual_cmr_num)
>  {
>  	struct tdx_module_output out;
>  	u64 ret;
> @@ -383,6 +383,18 @@ static int tdx_get_sysinfo(struct tdsysinfo_struct *tdsysinfo,
>  	return check_cmrs(cmr_array, actual_cmr_num);
>  }
>
> +const struct tdsysinfo_struct *tdx_get_sysinfo(void)
> +{
> +       const struct tdsysinfo_struct *r = NULL;
> +
> +       mutex_lock(&tdx_module_lock);
> +       if (tdx_module_status == TDX_MODULE_INITIALIZED)
> +	       r = &tdx_sysinfo;
> +       mutex_unlock(&tdx_module_lock);
> +       return r;
> +}
> +EXPORT_SYMBOL_GPL(tdx_get_sysinfo);
> +
>  /*
>   * Skip the memory region below 1MB.  Return true if the entire
>   * region is skipped.  Otherwise, the updated range is returned.
> @@ -1106,7 +1118,7 @@ static int init_tdx_module(void)
>  	if (ret)
>  		goto out;
>
> -	ret = tdx_get_sysinfo(&tdx_sysinfo, tdx_cmr_array, &tdx_cmr_num);
> +	ret = __tdx_get_sysinfo(&tdx_sysinfo, tdx_cmr_array, &tdx_cmr_num);
>  	if (ret)
>  		goto out;
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> index e0309558be13..c08e4ee2d0bf 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.h
> +++ b/arch/x86/virt/vmx/tdx/tdx.h
> @@ -65,58 +65,6 @@ struct cmr_info {
>  #define MAX_CMRS			32
>  #define CMR_INFO_ARRAY_ALIGNMENT	512
>
> -struct cpuid_config {
> -	u32	leaf;
> -	u32	sub_leaf;
> -	u32	eax;
> -	u32	ebx;
> -	u32	ecx;
> -	u32	edx;
> -} __packed;
> -
> -#define TDSYSINFO_STRUCT_SIZE		1024
> -#define TDSYSINFO_STRUCT_ALIGNMENT	1024
> -
> -struct tdsysinfo_struct {
> -	/* TDX-SEAM Module Info */
> -	u32	attributes;
> -	u32	vendor_id;
> -	u32	build_date;
> -	u16	build_num;
> -	u16	minor_version;
> -	u16	major_version;
> -	u8	reserved0[14];
> -	/* Memory Info */
> -	u16	max_tdmrs;
> -	u16	max_reserved_per_tdmr;
> -	u16	pamt_entry_size;
> -	u8	reserved1[10];
> -	/* Control Struct Info */
> -	u16	tdcs_base_size;
> -	u8	reserved2[2];
> -	u16	tdvps_base_size;
> -	u8	tdvps_xfam_dependent_size;
> -	u8	reserved3[9];
> -	/* TD Capabilities */
> -	u64	attributes_fixed0;
> -	u64	attributes_fixed1;
> -	u64	xfam_fixed0;
> -	u64	xfam_fixed1;
> -	u8	reserved4[32];
> -	u32	num_cpuid_config;
> -	/*
> -	 * The actual number of CPUID_CONFIG depends on above
> -	 * 'num_cpuid_config'.  The size of 'struct tdsysinfo_struct'
> -	 * is 1024B defined by TDX architecture.  Use a union with
> -	 * specific padding to make 'sizeof(struct tdsysinfo_struct)'
> -	 * equal to 1024.
> -	 */
> -	union {
> -		struct cpuid_config	cpuid_configs[0];
> -		u8			reserved5[892];
> -	};
> -} __packed __aligned(TDSYSINFO_STRUCT_ALIGNMENT);
> -
>  struct tdmr_reserved_area {
>  	u64 offset;
>  	u64 size;
> --
> 2.25.1
>