diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/cpu/x86/mtrr.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h index 15a5cad090..38c3f7cd0a 100644 --- a/src/include/cpu/x86/mtrr.h +++ b/src/include/cpu/x86/mtrr.h @@ -74,7 +74,11 @@ int x86_mtrr_check(void); /* ROM caching can be used after variable MTRRs are set up. Beware that * enabling CONFIG_CACHE_ROM will eat through quite a few MTRRs based on * one's IO hole size and WRCOMB resources. Be sure to check the console - * log when enabling CONFIG_CACHE_ROM or adding WRCOMB resources. */ + * log when enabling CONFIG_CACHE_ROM or adding WRCOMB resources. Beware that + * on CPUs with core-scoped MTRR registers such as hyperthreaded CPUs the + * rom caching will be disabled if all threads run the MTRR code. Therefore, + * one needs to call x86_mtrr_enable_rom_caching() after all threads of the + * same core have run the MTRR code. */ #if CONFIG_CACHE_ROM void x86_mtrr_enable_rom_caching(void); void x86_mtrr_disable_rom_caching(void); |