+ print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,
+ sev_cmd_buffer_len(cmd), false);
+ return ret;
... and here you return psp_ret == 0 even though something failed.
What I think you should do is not touch @psp_ret when you return before
the SEV command executes and *when* you return, set @psp_ret accordingly
to denote the status of the command execution.
Or if you're touching it before you execute the SEV
command and you return early, it should say something like
PSP_CMDRESP_COMMAND_DIDNT_EXECUTE or so, to tell the caller exactly what