| Date | Tue, 25 Jan 2022 14:48:51 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v8 33/40] x86/compressed/64: add identity mapping for Confidential Computing blob |
| |
On Fri, Dec 10, 2021 at 09:43:25AM -0600, Brijesh Singh wrote: > +static void sev_prep_identity_maps(void) > +{ > + /* > + * The ConfidentialComputing blob is used very early in uncompressed > + * kernel to find the in-memory cpuid table to handle cpuid > + * instructions. Make sure an identity-mapping exists so it can be > + * accessed after switchover. > + */ > + if (sev_snp_enabled()) { > + struct cc_blob_sev_info *cc_info = > + (void *)(unsigned long)boot_params->cc_blob_address; > + > + add_identity_map((unsigned long)cc_info, > + (unsigned long)cc_info + sizeof(*cc_info)); > + add_identity_map((unsigned long)cc_info->cpuid_phys, > + (unsigned long)cc_info->cpuid_phys + cc_info->cpuid_len); > + } > + > + sev_verify_cbit(top_level_pgt); > +} > +
Also, that function can just as well live in compressed/sev.c and you can export add_identity_map() instead.
That latter function calls kernel_ident_mapping_init() which is already exported. add_identity_map() doesn't do anything special and it is limited to the decompressor kernel so nothing stands in the way of exporting it in a pre-patch and renaming it there to kernel_add_identity_map() or so...
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
|