Re: [PATCH v6 08/22] x86/virt/seamldr: Allocate and populate a module update request

[Kiryl Shutsemau]

On Thu, Mar 26, 2026 at 01:43:59AM -0700, Chao Gao wrote:
> P-SEAMLDR uses the SEAMLDR_PARAMS structure to describe TDX module
> update requests. This structure contains physical addresses pointing to
> the module binary and its signature file (or sigstruct), along with an
> update scenario field.
> 
> TDX modules are distributed in the tdx_blob format defined in
> blob_structure.txt from the "Intel TDX module Binaries Repository". A
> tdx_blob contains a header, sigstruct, and module binary. This is also the
> format supplied by the userspace to the kernel.
> 
> Parse the tdx_blob format and populate a SEAMLDR_PARAMS structure
> accordingly. This structure will be passed to P-SEAMLDR to initiate the
> update.
> 
> Note that the sigstruct_pa field in SEAMLDR_PARAMS has been extended to
> a 4-element array. The updated "SEAM Loader (SEAMLDR) Interface
> Specification" will be published separately. P-SEAMLDR compatibility
> validation (such as 4KB vs 16KB sigstruct support) is left to userspace,
> which must verify the P-SEAMLDR version meets the TDX module's minimum
> requirements.
> 
> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
> Reviewed-by: Tony Lindgren <tony.lindgren@xxxxxxxxxxxxxxx>
> Reviewed-by: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>
> Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>

Reviewed-by: Kiryl Shutsemau (Meta) <kas@xxxxxxxxxx>

See nit below.

> +static struct seamldr_params *init_seamldr_params(const u8 *data, u32 size)
> +{
> +	const struct tdx_blob *blob = (const void *)data;
> +	int module_size, sig_size;
> +	const void *sig, *module;
> +
> +	/* Ensure the size is valid otherwise reading any field from the blob may overflow. */

Comment is too long for single line. Make it multi line.

> +	if (size <= sizeof(struct tdx_blob) || size <= blob->offset_of_module)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (blob->version != TDX_BLOB_VERSION_1) {
> +		pr_err("unsupported blob version: %x\n", blob->version);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	/* Split the blob into a sigstruct and a module. */
> +	sig		= blob->data;
> +	sig_size	= blob->offset_of_module - sizeof(struct tdx_blob);
> +	module		= data + blob->offset_of_module;
> +	module_size	= size - blob->offset_of_module;
> +
> +	if (sig_size <= 0 || module_size <= 0 || blob->length != size)
> +		return ERR_PTR(-EINVAL);
> +
> +	return alloc_seamldr_params(module, module_size, sig, sig_size);
> +}

-- 
  Kiryl Shutsemau / Kirill A. Shutemov