diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-04-02 09:59:33 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-14 19:17:12 +0200 |
| commit | fb49e1bb20614a081b912e4d01ccbe096602d46a (patch) | |
| tree | 6ebc4ced0e54a18c4ad5aaadccbc3aab94b37c5c /arch | |
| parent | 08831a92501f68f9b6e5f43ae032d0b9b2299045 (diff) | |
x86/speculation/mds: Add mds=full,nosmt cmdline option
commit d71eb0ce109a124b0fa714832823b9452f2762cf upstream
Add the mds=full,nosmt cmdline option. This is like mds=full, but with
SMT disabled if the CPU is vulnerable.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index bcc110a85830..4939addbd758 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -221,6 +221,7 @@ static void x86_amd_ssb_disable(void) /* Default mitigation for L1TF-affected CPUs */ static enum mds_mitigations mds_mitigation __ro_after_init = MDS_MITIGATION_FULL; +static bool mds_nosmt __ro_after_init = false; static const char * const mds_strings[] = { [MDS_MITIGATION_OFF] = "Vulnerable", @@ -238,8 +239,13 @@ static void __init mds_select_mitigation(void) if (mds_mitigation == MDS_MITIGATION_FULL) { if (!boot_cpu_has(X86_FEATURE_MD_CLEAR)) mds_mitigation = MDS_MITIGATION_VMWERV; + static_branch_enable(&mds_user_clear); + + if (mds_nosmt && !boot_cpu_has(X86_BUG_MSBDS_ONLY)) + cpu_smt_disable(false); } + pr_info("%s\n", mds_strings[mds_mitigation]); } @@ -255,6 +261,10 @@ static int __init mds_cmdline(char *str) mds_mitigation = MDS_MITIGATION_OFF; else if (!strcmp(str, "full")) mds_mitigation = MDS_MITIGATION_FULL; + else if (!strcmp(str, "full,nosmt")) { + mds_mitigation = MDS_MITIGATION_FULL; + mds_nosmt = true; + } return 0; } |