Re: [PATCH 5/9] x86/virt/tdx: Move field mapping table of getting TDMR info to function local

Nikolay Borisov
2024-06-18T11:47:55Z

On 16.06.24 г. 15:01 ч., Kai Huang wrote:
> For now the kernel only reads "TD Memory Region" (TDMR) related global
> metadata fields to a 'struct tdx_tdmr_sysinfo' for initializing the TDX
> module. The kernel populates the relevant metadata fields into the
> structure using a "field mapping table" of metadata field IDs and the
> structure members.
>
> Currently the scope of this "field mapping table" is the entire C file.
> Future changes will need to read more global metadata fields that will
> be organized in other structures and use this kind of field mapping
> tables for other structures too.
>
> Move the field mapping table to the function local to limit its scope so
> that the same name can also be used by other functions.

nit: I think all of this could be condensed simply to :

"The mapping table is only used by foo() so move it there, no functional
changes". The consideration for future usage seems somewhat moot with
respect to such a trivial change. In any case:

Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>

>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> arch/x86/virt/vmx/tdx/tdx.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index c68fbaf4aa15..fad42014ca37 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -322,17 +322,17 @@ static int stbuf_read_sysmd_multi(const struct field_mapping *fields,
> #define TD_SYSINFO_MAP_TDMR_INFO(_field_id, _member) \
> TD_SYSINFO_MAP(_field_id, struct tdx_tdmr_sysinfo, _member)
>
> -/* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */
> -static const struct field_mapping fields[] = {
> - 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]),
> -};
> -
> static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
> {
> + /* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */
> + static const struct field_mapping fields[] = {
> + 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]),
> + };
> +
> /* Populate 'tdmr_sysinfo' fields using the mapping structure above: */
> return stbuf_read_sysmd_multi(fields, ARRAY_SIZE(fields), tdmr_sysinfo);
> }