diff options
| -rw-r--r-- | arch/x86/include/asm/microcode.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/intel.c | 37 |
2 files changed, 35 insertions, 5 deletions
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h index 0ee6ed0ff2bf..695e569159c1 100644 --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -38,7 +38,8 @@ struct microcode_header_intel { unsigned int datasize; unsigned int totalsize; unsigned int metasize; - unsigned int reserved[2]; + unsigned int min_req_ver; + unsigned int reserved; }; struct microcode_intel { diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 14aa4c6d4c14..6024feb98d29 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -473,16 +473,40 @@ static enum ucode_state apply_microcode_late(int cpu) return ret; } +static bool ucode_validate_minrev(struct microcode_header_intel *mc_header) +{ + int cur_rev = boot_cpu_data.microcode; + + /* + * When late-loading, ensure the header declares a minimum revision + * required to perform a late-load. The previously reserved field + * is 0 in older microcode blobs. + */ + if (!mc_header->min_req_ver) { + pr_info("Unsafe microcode update: Microcode header does not specify a required min version\n"); + return false; + } + + /* + * Check whether the current revision is either greater or equal to + * to the minimum revision specified in the header. + */ + if (cur_rev < mc_header->min_req_ver) { + pr_info("Unsafe microcode update: Current revision 0x%x too old\n", cur_rev); + pr_info("Current should be at 0x%x or higher. Use early loading instead\n", mc_header->min_req_ver); + return false; + } + return true; +} + static enum ucode_state parse_microcode_blobs(int cpu, struct iov_iter *iter) { struct ucode_cpu_info *uci = ucode_cpu_info + cpu; + bool is_safe, new_is_safe = false; int cur_rev = uci->cpu_sig.rev; unsigned int curr_mc_size = 0; u8 *new_mc = NULL, *mc = NULL; - if (force_minrev) - return UCODE_NFOUND; - while (iov_iter_count(iter)) { struct microcode_header_intel mc_header; unsigned int mc_size, data_size; @@ -525,9 +549,14 @@ static enum ucode_state parse_microcode_blobs(int cpu, struct iov_iter *iter) if (!intel_find_matching_signature(mc, &uci->cpu_sig)) continue; + is_safe = ucode_validate_minrev(&mc_header); + if (force_minrev && !is_safe) + continue; + kvfree(new_mc); cur_rev = mc_header.rev; new_mc = mc; + new_is_safe = is_safe; mc = NULL; } @@ -539,7 +568,7 @@ static enum ucode_state parse_microcode_blobs(int cpu, struct iov_iter *iter) return UCODE_NFOUND; ucode_patch_late = (struct microcode_intel *)new_mc; - return UCODE_NEW; + return new_is_safe ? UCODE_NEW_SAFE : UCODE_NEW; fail: kvfree(mc); |