Re: [PATCH v19 003/130] x86/virt/tdx: Unbind global metadata read with 'struct tdx_tdmr_sysinfo'

[Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>]

On 2/26/2024 4:25 PM, isaku.yamahata@xxxxxxxxx wrote:
> From: Kai Huang <kai.huang@xxxxxxxxx>
>
> For now the kernel only reads TDMR related global metadata fields for
> module initialization, and the metadata read code only works with the
> 'struct tdx_tdmr_sysinfo'.
>
> KVM will need to read a bunch of non-TDMR related metadata to create and
> run TDX guests.  It's essential to provide a generic metadata read
> infrastructure which is not bound to any specific structure.
>
> To start providing such infrastructure, unbound the metadata read with
> the 'struct tdx_tdmr_sysinfo'.
>
> Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>

> ---
>   arch/x86/virt/vmx/tdx/tdx.c | 25 ++++++++++++++-----------
>   1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index cdcb3332bc5d..eb208da4ff63 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -273,9 +273,9 @@ static int read_sys_metadata_field(u64 field_id, u64 *data)
>   
>   static int read_sys_metadata_field16(u64 field_id,
>   				     int offset,
> -				     struct tdx_tdmr_sysinfo *ts)
> +				     void *stbuf)
>   {
> -	u16 *ts_member = ((void *)ts) + offset;
> +	u16 *st_member = stbuf + offset;
>   	u64 tmp;
>   	int ret;
>   
> @@ -287,7 +287,7 @@ static int read_sys_metadata_field16(u64 field_id,
>   	if (ret)
>   		return ret;
>   
> -	*ts_member = tmp;
> +	*st_member = tmp;
>   
>   	return 0;
>   }
> @@ -297,19 +297,22 @@ struct field_mapping {
>   	int offset;
>   };
>   
> -#define TD_SYSINFO_MAP(_field_id, _member) \
> -	{ .field_id = MD_FIELD_ID_##_field_id,	   \
> -	  .offset   = offsetof(struct tdx_tdmr_sysinfo, _member) }
> +#define TD_SYSINFO_MAP(_field_id, _struct, _member)	\
> +	{ .field_id = MD_FIELD_ID_##_field_id,		\
> +	  .offset   = offsetof(_struct, _member) }
> +
> +#define TD_SYSINFO_MAP_TDMR_INFO(_field_id, _member)	\
> +	TD_SYSINFO_MAP(_field_id, struct tdx_tdmr_sysinfo, _member)
>   
>   static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
>   {
>   	/* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */
>   	const struct field_mapping fields[] = {
> -		TD_SYSINFO_MAP(MAX_TDMRS,	      max_tdmrs),
> -		TD_SYSINFO_MAP(MAX_RESERVED_PER_TDMR, max_reserved_per_tdmr),
> -		TD_SYSINFO_MAP(PAMT_4K_ENTRY_SIZE,    pamt_entry_size[TDX_PS_4K]),
> -		TD_SYSINFO_MAP(PAMT_2M_ENTRY_SIZE,    pamt_entry_size[TDX_PS_2M]),
> -		TD_SYSINFO_MAP(PAMT_1G_ENTRY_SIZE,    pamt_entry_size[TDX_PS_1G]),
> +		TD_SYSINFO_MAP_TDMR_INFO(MAX_TDMRS,		max_tdmrs),
> +		TD_SYSINFO_MAP_TDMR_INFO(MAX_RESERVED_PER_TDMR, max_reserved_per_tdmr),
> +		TD_SYSINFO_MAP_TDMR_INFO(PAMT_4K_ENTRY_SIZE,    pamt_entry_size[TDX_PS_4K]),
> +		TD_SYSINFO_MAP_TDMR_INFO(PAMT_2M_ENTRY_SIZE,    pamt_entry_size[TDX_PS_2M]),
> +		TD_SYSINFO_MAP_TDMR_INFO(PAMT_1G_ENTRY_SIZE,    pamt_entry_size[TDX_PS_1G]),
>   	};
>   	int ret;
>   	int i;