Allocate and populate a module update request, i.e., struct seamldr_params, as defined in "SEAM Loader (SEAMLDR) Interface Specification" [1], Revision 343755-004, Section 3.2. struct seamldr_params includes a module binary, a sigstruct file, and an update scenario. Parse the bitstream format, as defined by Intel, to extract the binary and the sigstruct. Currently, only the "UPDATE" scenario is supported. Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx> Tested-by: Farrah Chen <farrah.chen@xxxxxxxxx> Link: https://cdrdv2.intel.com/v1/dl/getContent/733584 [1] --- arch/x86/virt/vmx/tdx/seamldr.c | 145 +++++++++++++++++++++++++++++++- 1 file changed, 144 insertions(+), 1 deletion(-) diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c index da862e71ebce..cdf85dff6d69 100644 --- a/arch/x86/virt/vmx/tdx/seamldr.c +++ b/arch/x86/virt/vmx/tdx/seamldr.c @@ -11,6 +11,8 @@ #include <linux/firmware.h> #include <linux/gfp.h> #include <linux/kobject.h> +#include <linux/mm.h> +#include <linux/slab.h> #include <linux/sysfs.h> #include "tdx.h" @@ -41,6 +43,26 @@ struct tdx_status { DECLARE_BITMAP(fw_state, TDX_FW_STATE_BITS); }; +/* SEAMLDR can accept up to 496 4KB pages for TDX module binary */ +#define SEAMLDR_MAX_NR_MODULE_4KB_PAGES 496 + +/* scenario field in struct seamldr_params */ +#define SEAMLDR_SCENARIO_UPDATE 1 + +/* + * Passed to P-SEAMLDR to describe information about the TDX module to install. + * Defined in "SEAM Loader (SEAMLDR) Interface Specification", Revision + * 343755-003, Section 3.2. + */ +struct seamldr_params { + u32 version; + u32 scenario; + u64 sigstruct_pa; + u8 reserved[104]; + u64 num_module_pages; + u64 mod_pages_pa_list[SEAMLDR_MAX_NR_MODULE_4KB_PAGES]; +} __packed; + struct fw_upload *tdx_fwl; static struct tdx_status tdx_status; static struct seamldr_info seamldr_info __aligned(256); @@ -113,9 +135,130 @@ int get_seamldr_info(void) return seamldr_call(P_SEAMLDR_INFO, &args); } +static void free_seamldr_params(struct seamldr_params *params) +{ + free_page((unsigned long)params); +} + +/* Allocate and populate a seamldr_params */ +static struct seamldr_params *alloc_seamldr_params(const void *module, int module_size, + const void *sig, int sig_size) +{ + struct seamldr_params *params; + const u8 *ptr; + int i; + + BUILD_BUG_ON(sizeof(struct seamldr_params) != SZ_4K); + if (module_size > SEAMLDR_MAX_NR_MODULE_4KB_PAGES * SZ_4K) + return ERR_PTR(-EINVAL); + + /* current seamldr_params accepts one 4KB-page for sigstruct */ + if (sig_size != SZ_4K) + return ERR_PTR(-EINVAL); + + params = (struct seamldr_params *)get_zeroed_page(GFP_KERNEL); + if (!params) + return ERR_PTR(-ENOMEM); + + params->scenario = SEAMLDR_SCENARIO_UPDATE; + params->sigstruct_pa = (vmalloc_to_pfn(sig) << PAGE_SHIFT) + + ((unsigned long)sig & ~PAGE_MASK); + params->num_module_pages = DIV_ROUND_UP(module_size, SZ_4K); + + ptr = module; + for (i = 0; i < params->num_module_pages; i++) { + params->mod_pages_pa_list[i] = (vmalloc_to_pfn(ptr) << PAGE_SHIFT) + + ((unsigned long)ptr & ~PAGE_MASK); + ptr += SZ_4K; + } + + return params; +} + +struct tdx_blob { + u16 version; + u16 checksum; + u32 offset_of_module; + u8 signature[8]; + u32 len; + u32 resv1; + u64 resv2[509]; + u8 data[]; +} __packed; + +/* Verify that the checksum of the entire blob is zero */ +static bool verify_checksum(const struct tdx_blob *blob) +{ + u32 size = blob->len; + u16 checksum = 0; + const u16 *p; + int i; + + /* Handle the last byte if the size is odd */ + if (size % 2) { + checksum += *((const u8 *)blob + size - 1); + size--; + } + + p = (const u16 *)blob; + for (i = 0; i < size; i += 2) { + checksum += *p; + p++; + } + + return !checksum; +} + +static struct seamldr_params *init_seamldr_params(const u8 *data, u32 size) +{ + const struct tdx_blob *blob = (const void *)data; + const void *sig, *module; + int module_size, sig_size; + + /* Split the given 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->len != size) + return ERR_PTR(-EINVAL); + + if (memcmp(blob->signature, "TDX-BLOB", 8)) { + pr_err("invalid signature\n"); + return ERR_PTR(-EINVAL); + } + + if (!verify_checksum(blob)) { + pr_err("invalid checksum\n"); + return ERR_PTR(-EINVAL); + } + + return alloc_seamldr_params(module, module_size, sig, sig_size); +} + +/* + * Temporary flag to guard TD-Preserving updates. This will be removed once + * all necessary components for its support are integrated. + */ +static bool td_preserving_ready; + +DEFINE_FREE(free_seamldr_params, struct seamldr_params *, + if (!IS_ERR_OR_NULL(_T)) free_seamldr_params(_T)) + static int seamldr_install_module(const u8 *data, u32 size) { - return -EOPNOTSUPP; + if (!td_preserving_ready) + return -EOPNOTSUPP; + + struct seamldr_params *params __free(free_seamldr_params) = + init_seamldr_params(data, size); + if (IS_ERR(params)) + return PTR_ERR(params); + + /* TODO: Install and initialize the new TDX module */ + + return 0; } static enum fw_upload_err tdx_fw_prepare(struct fw_upload *fwl, -- 2.47.1
