Messages in this thread | | | Subject | Re: [GRUB PATCH RFC 15/18] i386/txt: Add Intel TXT core implementation | From | Krystian Hebel <> | Date | Fri, 22 May 2020 15:24:01 +0200 |
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On 05.05.2020 01:21, Daniel Kiper wrote: > +static grub_err_t > +init_txt_heap (struct grub_slaunch_params *slparams, struct grub_txt_acm_header *sinit) > +{ > + grub_uint8_t *txt_heap; > + grub_uint32_t os_sinit_data_ver, sinit_caps; > + grub_uint64_t *size; > + struct grub_txt_os_mle_data *os_mle_data; > + struct grub_txt_os_sinit_data *os_sinit_data; > + struct grub_txt_heap_end_element *heap_end_element; > + struct grub_txt_heap_event_log_pointer2_1_element *heap_event_log_pointer2_1_element; > +#ifdef GRUB_MACHINE_EFI > + struct grub_acpi_rsdp_v20 *rsdp; > +#endif > + > + /* BIOS data already verified in grub_txt_verify_platform(). */ > + > + txt_heap = grub_txt_get_heap (); > + > + /* OS/loader to MLE data. */ > + > + os_mle_data = grub_txt_os_mle_data_start (txt_heap); > + size = (grub_uint64_t *) ((grub_addr_t) os_mle_data - sizeof (grub_uint64_t)); There is 'grub_txt_os_mle_data_size()' in previous patch, it would look better. > + *size = sizeof (*os_mle_data) + sizeof (grub_uint64_t); > + > + grub_memset (os_mle_data, 0, sizeof (*os_mle_data)); > + > + os_mle_data->version = GRUB_SL_OS_MLE_STRUCT_VERSION; > + os_mle_data->zero_page_addr = (grub_uint32_t)(grub_addr_t) slparams->params; > + os_mle_data->saved_misc_enable_msr = grub_rdmsr (GRUB_MSR_X86_MISC_ENABLE); > + > + os_mle_data->ap_wake_block = slparams->ap_wake_block; > + > + save_mtrrs (os_mle_data); > + > + /* OS/loader to SINIT data. */ > + > + os_sinit_data_ver = grub_txt_supported_os_sinit_data_ver (sinit); > + > + if (os_sinit_data_ver < OS_SINIT_DATA_MIN_VER) > + return grub_error (GRUB_ERR_BAD_DEVICE, > + N_("unsupported OS to SINIT data version in SINIT ACM: %d" > + " expected >= %d"), os_sinit_data_ver, OS_SINIT_DATA_MIN_VER); > + > + os_sinit_data = grub_txt_os_sinit_data_start (txt_heap); > + size = (grub_uint64_t *) ((grub_addr_t) os_sinit_data - sizeof (grub_uint64_t)); Ditto > + > + *size = sizeof(grub_uint64_t) + sizeof (struct grub_txt_os_sinit_data) + > + sizeof (struct grub_txt_heap_end_element); > + > + if (grub_get_tpm_ver () == GRUB_TPM_12) > + *size += sizeof (struct grub_txt_heap_tpm_event_log_element); > + else if (grub_get_tpm_ver () == GRUB_TPM_20) > + *size += sizeof (struct grub_txt_heap_event_log_pointer2_1_element); > + else > + return grub_error (GRUB_ERR_BAD_DEVICE, N_("unsupported TPM version")); > + > + grub_memset (os_sinit_data, 0, *size); > + > +#ifdef GRUB_MACHINE_EFI > + rsdp = grub_acpi_get_rsdpv2 (); > + > + if (rsdp == NULL) > + return grub_printf ("WARNING: ACPI RSDP 2.0 missing\n"); > + > + os_sinit_data->efi_rsdt_ptr = (grub_uint64_t)(grub_addr_t) rsdp; > +#endif > + > + os_sinit_data->mle_ptab = slparams->mle_ptab_target; > + os_sinit_data->mle_size = slparams->mle_size; > + > + os_sinit_data->mle_hdr_base = slparams->mle_header_offset; > + > + /* TODO: Check low PMR with RMRR. Look at relevant tboot code too. */ > + /* TODO: Kernel should not allocate any memory outside of PMRs regions!!! */ > + os_sinit_data->vtd_pmr_lo_base = 0; > + os_sinit_data->vtd_pmr_lo_size = ALIGN_DOWN (grub_mmap_get_highest (0x100000000), > + GRUB_TXT_PMR_ALIGN); > + > + os_sinit_data->vtd_pmr_hi_base = ALIGN_UP (grub_mmap_get_lowest (0x100000000), > + GRUB_TXT_PMR_ALIGN); > + os_sinit_data->vtd_pmr_hi_size = ALIGN_DOWN (grub_mmap_get_highest (0xffffffffffffffff), > + GRUB_TXT_PMR_ALIGN); > + os_sinit_data->vtd_pmr_hi_size -= os_sinit_data->vtd_pmr_hi_base; Could it be done with just one PMR, from 0 to top of memory, or would TXT complain? > + > + grub_dprintf ("slaunch", > + "vtd_pmr_lo_base: 0x%" PRIxGRUB_UINT64_T " vtd_pmr_lo_size: 0x%" > + PRIxGRUB_UINT64_T " vtd_pmr_hi_base: 0x%" PRIxGRUB_UINT64_T > + " vtd_pmr_hi_size: 0x%" PRIxGRUB_UINT64_T "\n", > + os_sinit_data->vtd_pmr_lo_base, os_sinit_data->vtd_pmr_lo_size, > + os_sinit_data->vtd_pmr_hi_base, os_sinit_data->vtd_pmr_hi_size); > + > > <snip> > > +/* > + * The MLE page tables have to be below the MLE and have no special regions in > + * between them and the MLE (this is a bit of an unwritten rule). > + * 20 pages are carved out of memory below the MLE. That leave 18 page table > + * pages that can cover up to 36M . > + * can only contain 4k pages > + * > + * TODO: TXT Spec p.32; List section name and number with PT MLE requirments here. > + * > + * TODO: This function is not able to cover MLEs larger than 1 GiB. Fix it!!! > + * After fixing inrease GRUB_TXT_MLE_MAX_SIZE too. > + */
What do you mean by "special regions"? In TXT spec it is written that there may be no holes in the virtual address space:
"There may not be any invalid (not-present) page table entries after the first valid entry (i.e. there may not be any gaps in the MLE’s linear address space)."
Also that spec: "A breadth-first search of page tables must produce increasing physical addresses."
Maybe I misunderstood, but does it mean that the paging structures themselves cannot be mapped? Or does it apply to the page tables only, not to the addresses of pages in PTEs?
> +void > +grub_txt_setup_mle_ptab (struct grub_slaunch_params *slparams) > +{ > + grub_uint8_t *pg_dir, *pg_dir_ptr_tab = slparams->mle_ptab_mem, *pg_tab; IMHO using 'grub_uint64_t' would result in less type casting and cleaner code below. > + grub_uint32_t mle_off = 0, pd_off = 0; > + grub_uint64_t *pde, *pte; > + > + grub_memset (pg_dir_ptr_tab, 0, slparams->mle_ptab_size); > + > + pg_dir = pg_dir_ptr_tab + GRUB_PAGE_SIZE; > + pg_tab = pg_dir + GRUB_PAGE_SIZE; > + > + /* Only use first entry in page dir ptr table */ > + *(grub_uint64_t *)pg_dir_ptr_tab = MAKE_PT_MLE_ENTRY(pg_dir); > + > + /* Start with first entry in page dir */ > + *(grub_uint64_t *)pg_dir = MAKE_PT_MLE_ENTRY(pg_tab); > + > + pte = (grub_uint64_t *)pg_tab; > + pde = (grub_uint64_t *)pg_dir; > + > + do > + { > + *pte = MAKE_PT_MLE_ENTRY(slparams->mle_start + mle_off); > + > + pte++; > + mle_off += GRUB_PAGE_SIZE; > + > + if (!(++pd_off % 512)) > + { > + /* Break if we don't need any additional page entries */ > + if (mle_off >= slparams->mle_size) > + break; > + pde++; > + *pde = MAKE_PT_MLE_ENTRY(pte); > + } > + } while (mle_off < slparams->mle_size); > +} > > <snip> > > +grub_err_t > +grub_txt_boot_prepare (struct grub_slaunch_params *slparams) > +{ > + grub_err_t err; > + struct grub_txt_mle_header *mle_header; > + struct grub_txt_acm_header *sinit_base; > + > + sinit_base = grub_txt_sinit_select (grub_slaunch_module ()); > + > + if (sinit_base == NULL) > + return grub_errno; > + > + err = init_txt_heap (slparams, sinit_base); > + > + if (err != GRUB_ERR_NONE) > + return err; > + > + /* Update the MLE header. */ > + mle_header = (struct grub_txt_mle_header *)(grub_addr_t) (slparams->mle_start + slparams->mle_header_offset); > + mle_header->first_valid_page = 0; > + mle_header->mle_end = slparams->mle_size; > + > + slparams->sinit_acm_base = (grub_uint32_t)(grub_addr_t) sinit_base; > + slparams->sinit_acm_size = sinit_base->size * 4; > + > + grub_tpm_relinquish_lcl (0); > + > + err = set_mtrrs_for_acmod (sinit_base); > + if (err) > + return grub_error (err, N_("secure launch failed to set MTRRs for ACM")); > + > + err = grub_txt_prepare_cpu (); > + if ( err ) > + return err; > + > + if (!(grub_rdmsr (GRUB_MSR_X86_APICBASE) & GRUB_MSR_X86_APICBASE_BSP)) > + return grub_error (GRUB_ERR_BAD_DEVICE, N_("secure launch must run on BSP")); This test should be the first one, before messing with TPM and MTTRs. > + > + return GRUB_ERR_NONE; > +} Best regards,
-- Krystian Hebel Firmware Engineer https://3mdeb.com | @3mdeb_com
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