| From: Andy Lutomirski <luto@kernel.org> |
| Date: Fri, 29 Jan 2016 11:42:58 -0800 |
| Subject: x86/mm: Add a 'noinvpcid' boot option to turn off INVPCID |
| |
| commit d12a72b844a49d4162f24cefdab30bed3f86730e upstream. |
| |
| This adds a chicken bit to turn off INVPCID in case something goes |
| wrong. It's an early_param() because we do TLB flushes before we |
| parse __setup() parameters. |
| |
| Signed-off-by: Andy Lutomirski <luto@kernel.org> |
| Reviewed-by: Borislav Petkov <bp@suse.de> |
| Cc: Andrew Morton <akpm@linux-foundation.org> |
| Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> |
| Cc: Andy Lutomirski <luto@amacapital.net> |
| Cc: Borislav Petkov <bp@alien8.de> |
| Cc: Brian Gerst <brgerst@gmail.com> |
| Cc: Dave Hansen <dave.hansen@linux.intel.com> |
| Cc: Denys Vlasenko <dvlasenk@redhat.com> |
| Cc: H. Peter Anvin <hpa@zytor.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Luis R. Rodriguez <mcgrof@suse.com> |
| Cc: Oleg Nesterov <oleg@redhat.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Toshi Kani <toshi.kani@hp.com> |
| Cc: linux-mm@kvack.org |
| Link: http://lkml.kernel.org/r/f586317ed1bc2b87aee652267e515b90051af385.1454096309.git.luto@kernel.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Cc: Hugh Dickins <hughd@google.com> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| Documentation/kernel-parameters.txt | 2 ++ |
| arch/x86/kernel/cpu/common.c | 16 ++++++++++++++++ |
| 2 files changed, 18 insertions(+) |
| |
| diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt |
| index 356bf4b4273b..b71a8ea90180 100644 |
| --- a/Documentation/kernel-parameters.txt |
| +++ b/Documentation/kernel-parameters.txt |
| @@ -1799,6 +1799,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. |
| |
| nointroute [IA-64] |
| |
| + noinvpcid [X86] Disable the INVPCID cpu feature. |
| + |
| nojitter [IA-64] Disables jitter checking for ITC timers. |
| |
| no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver |
| diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c |
| index 83df01dca3ac..1477e7046838 100644 |
| --- a/arch/x86/kernel/cpu/common.c |
| +++ b/arch/x86/kernel/cpu/common.c |
| @@ -155,6 +155,22 @@ static int __init x86_xsaveopt_setup(char *s) |
| } |
| __setup("noxsaveopt", x86_xsaveopt_setup); |
| |
| +static int __init x86_noinvpcid_setup(char *s) |
| +{ |
| + /* noinvpcid doesn't accept parameters */ |
| + if (s) |
| + return -EINVAL; |
| + |
| + /* do not emit a message if the feature is not present */ |
| + if (!boot_cpu_has(X86_FEATURE_INVPCID)) |
| + return 0; |
| + |
| + setup_clear_cpu_cap(X86_FEATURE_INVPCID); |
| + pr_info("noinvpcid: INVPCID feature disabled\n"); |
| + return 0; |
| +} |
| +early_param("noinvpcid", x86_noinvpcid_setup); |
| + |
| #ifdef CONFIG_X86_32 |
| static int cachesize_override __cpuinitdata = -1; |
| static int disable_x86_serial_nr __cpuinitdata = 1; |
| |