projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 9b9d3ba2 GKH |
1 | From e3ef0729359b15dcecbe1a5da4dfe32612a1590d Mon Sep 17 00:00:00 2001 |
| 2 | From: Josh Poimboeuf <jpoimboe@redhat.com> | |
| 3 | Date: Tue, 2 Apr 2019 09:59:33 -0500 | |
| 4 | Subject: [PATCH 18/30] x86/speculation/mds: Add mds=full,nosmt cmdline option | |
| 5 | ||
| 6 | commit d71eb0ce109a124b0fa714832823b9452f2762cf upstream | |
| 7 | ||
| 8 | Add the mds=full,nosmt cmdline option. This is like mds=full, but with | |
| 9 | SMT disabled if the CPU is vulnerable. | |
| 10 | ||
| 11 | Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> | |
| 12 | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> | |
| 13 | Reviewed-by: Tyler Hicks <tyhicks@canonical.com> | |
| 14 | Acked-by: Jiri Kosina <jkosina@suse.cz> | |
| 15 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 16 | --- | |
| 17 | Documentation/admin-guide/hw-vuln/mds.rst | 3 +++ | |
| 18 | Documentation/admin-guide/kernel-parameters.txt | 6 ++++-- | |
| 19 | arch/x86/kernel/cpu/bugs.c | 10 ++++++++++ | |
| 20 | 3 files changed, 17 insertions(+), 2 deletions(-) | |
| 21 | ||
| 22 | diff --git a/Documentation/admin-guide/hw-vuln/mds.rst b/Documentation/admin-guide/hw-vuln/mds.rst | |
| 23 | index 1de29d28903d..244ab47d1fb3 100644 | |
| 24 | --- a/Documentation/admin-guide/hw-vuln/mds.rst | |
| 25 | +++ b/Documentation/admin-guide/hw-vuln/mds.rst | |
| 26 | @@ -260,6 +260,9 @@ time with the option "mds=". The valid arguments for this option are: | |
| 27 | ||
| 28 | It does not automatically disable SMT. | |
| 29 | ||
| 30 | + full,nosmt The same as mds=full, with SMT disabled on vulnerable | |
| 31 | + CPUs. This is the complete mitigation. | |
| 32 | + | |
| 33 | off Disables MDS mitigations completely. | |
| 34 | ||
| 35 | ============ ============================================================= | |
| 36 | diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt | |
| 37 | index 290f0946f2ef..df8d10668b11 100644 | |
| 38 | --- a/Documentation/admin-guide/kernel-parameters.txt | |
| 39 | +++ b/Documentation/admin-guide/kernel-parameters.txt | |
| 40 | @@ -2335,8 +2335,10 @@ | |
| 41 | This parameter controls the MDS mitigation. The | |
| 42 | options are: | |
| 43 | ||
| 44 | - full - Enable MDS mitigation on vulnerable CPUs | |
| 45 | - off - Unconditionally disable MDS mitigation | |
| 46 | + full - Enable MDS mitigation on vulnerable CPUs | |
| 47 | + full,nosmt - Enable MDS mitigation and disable | |
| 48 | + SMT on vulnerable CPUs | |
| 49 | + off - Unconditionally disable MDS mitigation | |
| 50 | ||
| 51 | Not specifying this option is equivalent to | |
| 52 | mds=full. | |
| 53 | diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c | |
| 54 | index a7e54a91abc4..3f70da3a4e58 100644 | |
| 55 | --- a/arch/x86/kernel/cpu/bugs.c | |
| 56 | +++ b/arch/x86/kernel/cpu/bugs.c | |
| 57 | @@ -219,6 +219,7 @@ static void x86_amd_ssb_disable(void) | |
| 58 | ||
| 59 | /* Default mitigation for L1TF-affected CPUs */ | |
| 60 | static enum mds_mitigations mds_mitigation __ro_after_init = MDS_MITIGATION_FULL; | |
| 61 | +static bool mds_nosmt __ro_after_init = false; | |
| 62 | ||
| 63 | static const char * const mds_strings[] = { | |
| 64 | [MDS_MITIGATION_OFF] = "Vulnerable", | |
| 65 | @@ -236,8 +237,13 @@ static void __init mds_select_mitigation(void) | |
| 66 | if (mds_mitigation == MDS_MITIGATION_FULL) { | |
| 67 | if (!boot_cpu_has(X86_FEATURE_MD_CLEAR)) | |
| 68 | mds_mitigation = MDS_MITIGATION_VMWERV; | |
| 69 | + | |
| 70 | static_branch_enable(&mds_user_clear); | |
| 71 | + | |
| 72 | + if (mds_nosmt && !boot_cpu_has(X86_BUG_MSBDS_ONLY)) | |
| 73 | + cpu_smt_disable(false); | |
| 74 | } | |
| 75 | + | |
| 76 | pr_info("%s\n", mds_strings[mds_mitigation]); | |
| 77 | } | |
| 78 | ||
| 79 | @@ -253,6 +259,10 @@ static int __init mds_cmdline(char *str) | |
| 80 | mds_mitigation = MDS_MITIGATION_OFF; | |
| 81 | else if (!strcmp(str, "full")) | |
| 82 | mds_mitigation = MDS_MITIGATION_FULL; | |
| 83 | + else if (!strcmp(str, "full,nosmt")) { | |
| 84 | + mds_mitigation = MDS_MITIGATION_FULL; | |
| 85 | + mds_nosmt = true; | |
| 86 | + } | |
| 87 | ||
| 88 | return 0; | |
| 89 | } | |
| 90 | -- | |
| 91 | 2.21.0 | |
| 92 |