Kai Huang wrote:
> The TDX module provides a set of "global metadata fields". They report
> things like TDX module version, supported features, and fields related
> to create/run TDX guests and so on.
>
> Currently the kernel only reads "TD Memory Region" (TDMR) related fields
> for module initialization. There are immediate needs which require the
> TDX module initialization to read more global metadata including module
> version, supported features and "Convertible Memory Regions" (CMRs).
>
> Also, KVM will need to read more metadata fields to support baseline TDX
> guests. In the longer term, other TDX features like TDX Connect (which
> supports assigning trusted IO devices to TDX guest) may also require
> other kernel components such as pci/vt-d to access global metadata.
>
> To meet all those requirements, the idea is the TDX host core-kernel to
> to provide a centralized, canonical, and read-only structure for the
> global metadata that comes out from the TDX module for all kernel
> components to use.
>
> As the first step, introduce a new 'struct tdx_sysinfo' to track all
> global metadata fields.
>
> TDX categories global metadata fields into different "Class"es. E.g.,
> the current TDMR related fields are under class "TDMR Info". Instead of
> making 'struct tdx_sysinfo' a plain structure to contain all metadata
> fields, organize them in smaller structures based on the "Class".
>
> This allows those metadata fields to be used in finer granularity thus
> makes the code more clear. E.g., the current construct_tdmr() can just
> take the structure which contains "TDMR Info" metadata fields.
>
> Start with moving 'struct tdx_tdmr_sysinfo' to 'struct tdx_sysinfo', and
> rename 'struct tdx_tdmr_sysinfo' to 'struct tdx_sysinfo_tdmr_info' to
> make it consistent with the "class name".
How about 'struct tdx_sys_info' and 'struct tdx_sys_tdmr_info' to avoid
duplicating 'info' in the symbol name?
Do pure renames indpendent of logic changes to make patches like
this easier to read.
I would also move the pure rename to the front of the patches so the
reviewer spends as minimal amount of time with the deprecated name in
the set.
> Add a new function get_tdx_sysinfo() as the place to read all metadata
> fields, and call it at the beginning of init_tdx_module(). Move the
> existing get_tdx_tdmr_sysinfo() to get_tdx_sysinfo().
>
> Note there is a functional change: get_tdx_tdmr_sysinfo() is moved from
> after build_tdx_memlist() to before it, but it is fine to do so.
>
> Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
> ---
> arch/x86/virt/vmx/tdx/tdx.c | 29 +++++++++++++++++------------
> arch/x86/virt/vmx/tdx/tdx.h | 32 +++++++++++++++++++++++++-------
> 2 files changed, 42 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index 86c47db64e42..3253cdfa5207 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -320,11 +320,11 @@ 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)
> + TD_SYSINFO_MAP(_field_id, struct tdx_sysinfo_tdmr_info, _member)
>
> -static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
> +static int get_tdx_tdmr_sysinfo(struct tdx_sysinfo_tdmr_info *tdmr_sysinfo)
> {
> - /* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */
> + /* Map TD_SYSINFO fields into 'struct tdx_sysinfo_tdmr_info': */
> 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),
> @@ -337,6 +337,11 @@ static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo)
> return stbuf_read_sysmd_multi(fields, ARRAY_SIZE(fields), tdmr_sysinfo);
> }
>
> +static int get_tdx_sysinfo(struct tdx_sysinfo *sysinfo)
> +{
> + return get_tdx_tdmr_sysinfo(&sysinfo->tdmr_info);
> +}
> +
> /* Calculate the actual TDMR size */
> static int tdmr_size_single(u16 max_reserved_per_tdmr)
> {
> @@ -353,7 +358,7 @@ static int tdmr_size_single(u16 max_reserved_per_tdmr)
> }
>
> static int alloc_tdmr_list(struct tdmr_info_list *tdmr_list,
> - struct tdx_tdmr_sysinfo *tdmr_sysinfo)
> + struct tdx_sysinfo_tdmr_info *tdmr_sysinfo)
> {
> size_t tdmr_sz, tdmr_array_sz;
> void *tdmr_array;
> @@ -936,7 +941,7 @@ static int tdmrs_populate_rsvd_areas_all(struct tdmr_info_list *tdmr_list,
> */
> static int construct_tdmrs(struct list_head *tmb_list,
> struct tdmr_info_list *tdmr_list,
> - struct tdx_tdmr_sysinfo *tdmr_sysinfo)
> + struct tdx_sysinfo_tdmr_info *tdmr_sysinfo)
> {
> int ret;
>
> @@ -1109,9 +1114,13 @@ static int init_tdmrs(struct tdmr_info_list *tdmr_list)
>
> static int init_tdx_module(void)
> {
> - struct tdx_tdmr_sysinfo tdmr_sysinfo;
> + struct tdx_sysinfo sysinfo;
> int ret;
>
> + ret = get_tdx_sysinfo(&sysinfo);
> + if (ret)
> + return ret;
> +
> /*
> * To keep things simple, assume that all TDX-protected memory
> * will come from the page allocator. Make sure all pages in the
> @@ -1128,17 +1137,13 @@ static int init_tdx_module(void)
> if (ret)
> goto out_put_tdxmem;
>
> - ret = get_tdx_tdmr_sysinfo(&tdmr_sysinfo);
> - if (ret)
> - goto err_free_tdxmem;
> -
> /* Allocate enough space for constructing TDMRs */
> - ret = alloc_tdmr_list(&tdx_tdmr_list, &tdmr_sysinfo);
> + ret = alloc_tdmr_list(&tdx_tdmr_list, &sysinfo.tdmr_info);
> if (ret)
> goto err_free_tdxmem;
>
> /* Cover all TDX-usable memory regions in TDMRs */
> - ret = construct_tdmrs(&tdx_memlist, &tdx_tdmr_list, &tdmr_sysinfo);
> + ret = construct_tdmrs(&tdx_memlist, &tdx_tdmr_list, &sysinfo.tdmr_info);
> if (ret)
> goto err_free_tdmrs;
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> index 4e43cec19917..b5eb7c35f1dc 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.h
> +++ b/arch/x86/virt/vmx/tdx/tdx.h
> @@ -100,13 +100,6 @@ struct tdx_memblock {
> int nid;
> };
>
> -/* "TDMR info" part of "Global Scope Metadata" for constructing TDMRs */
> -struct tdx_tdmr_sysinfo {
> - u16 max_tdmrs;
> - u16 max_reserved_per_tdmr;
> - u16 pamt_entry_size[TDX_PS_NR];
> -};
> -
> /* Warn if kernel has less than TDMR_NR_WARN TDMRs after allocation */
> #define TDMR_NR_WARN 4
>
> @@ -119,4 +112,29 @@ struct tdmr_info_list {
> int max_tdmrs; /* How many 'tdmr_info's are allocated */
> };
>
> +/*
> + * Kernel-defined structures to contain "Global Scope Metadata".
> + *
> + * TDX global metadata fields are categorized by "Class". See the
> + * "global_metadata.json" in the "TDX 1.5 ABI Definitions".
> + *
> + * 'struct tdx_sysinfo' is the main structure to contain all metadata
> + * used by the kernel. It contains sub-structures with each reflecting
> + * the "Class" in the 'global_metadata.json'.
> + *
> + * Note not all metadata fields in each class are defined, only those
> + * used by the kernel are.
> + */
> +
> +/* Class "TDMR Info" */
> +struct tdx_sysinfo_tdmr_info {
> + u16 max_tdmrs;
> + u16 max_reserved_per_tdmr;
> + u16 pamt_entry_size[TDX_PS_NR];
> +};
> +
> +struct tdx_sysinfo {
> + struct tdx_sysinfo_tdmr_info tdmr_info;
> +};
I would just call this member 'tdmr' since the 'info' is already applied
by being in tdx_sys_info.
