1 files changed, 66 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index b1af22073e28..319bf989fad1 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -102,6 +102,59 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
                 ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
 }
 
+/*
+ * Early microcode releases for the Spectre v2 mitigation were broken.
+ * Information taken from;
+ * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/01/microcode-update-guidance.pdf
+ * - https://kb.vmware.com/s/article/52345
+ * - Microcode revisions observed in the wild
+ * - Release note from 20180108 microcode release
+ */
+struct sku_microcode {
+        u8 model;
+        u8 stepping;
+        u32 microcode;
+};
+static const struct sku_microcode spectre_bad_microcodes[] = {
+        { INTEL_FAM6_KABYLAKE_DESKTOP,  0x0B,   0x84 },
+        { INTEL_FAM6_KABYLAKE_DESKTOP,  0x0A,   0x84 },
+        { INTEL_FAM6_KABYLAKE_DESKTOP,  0x09,   0x84 },
+        { INTEL_FAM6_KABYLAKE_MOBILE,   0x0A,   0x84 },
+        { INTEL_FAM6_KABYLAKE_MOBILE,   0x09,   0x84 },
+        { INTEL_FAM6_SKYLAKE_X,         0x03,   0x0100013e },
+        { INTEL_FAM6_SKYLAKE_X,         0x04,   0x0200003c },
+        { INTEL_FAM6_SKYLAKE_MOBILE,    0x03,   0xc2 },
+        { INTEL_FAM6_SKYLAKE_DESKTOP,   0x03,   0xc2 },
+        { INTEL_FAM6_BROADWELL_CORE,    0x04,   0x28 },
+        { INTEL_FAM6_BROADWELL_GT3E,    0x01,   0x1b },
+        { INTEL_FAM6_BROADWELL_XEON_D,  0x02,   0x14 },
+        { INTEL_FAM6_BROADWELL_XEON_D,  0x03,   0x07000011 },
+        { INTEL_FAM6_BROADWELL_X,       0x01,   0x0b000025 },
+        { INTEL_FAM6_HASWELL_ULT,       0x01,   0x21 },
+        { INTEL_FAM6_HASWELL_GT3E,      0x01,   0x18 },
+        { INTEL_FAM6_HASWELL_CORE,      0x03,   0x23 },
+        { INTEL_FAM6_HASWELL_X,         0x02,   0x3b },
+        { INTEL_FAM6_HASWELL_X,         0x04,   0x10 },
+        { INTEL_FAM6_IVYBRIDGE_X,       0x04,   0x42a },
+        /* Updated in the 20180108 release; blacklist until we know otherwise */
+        { INTEL_FAM6_ATOM_GEMINI_LAKE,  0x01,   0x22 },
+        /* Observed in the wild */
+        { INTEL_FAM6_SANDYBRIDGE_X,     0x06,   0x61b },
+        { INTEL_FAM6_SANDYBRIDGE_X,     0x07,   0x712 },
+};
+
+static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
+                if (c->x86_model == spectre_bad_microcodes[i].model &&
+                    c->x86_mask == spectre_bad_microcodes[i].stepping)
+                        return (c->microcode <= spectre_bad_microcodes[i].microcode);
+        }
+        return false;
+}
+
 static void early_init_intel(struct cpuinfo_x86 *c)
 {
         u64 misc_enable;
@@ -122,6 +175,19 @@ static void early_init_intel(struct cpuinfo_x86 *c)
         if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64))
                 c->microcode = intel_get_microcode_revision();
 
+        /* Now if any of them are set, check the blacklist and clear the lot */
+        if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) ||
+             cpu_has(c, X86_FEATURE_INTEL_STIBP) ||
+             cpu_has(c, X86_FEATURE_IBRS) || cpu_has(c, X86_FEATURE_IBPB) ||
+             cpu_has(c, X86_FEATURE_STIBP)) && bad_spectre_microcode(c)) {
+                pr_warn("Intel Spectre v2 broken microcode detected; disabling Speculation Control\n");
+                setup_clear_cpu_cap(X86_FEATURE_IBRS);
+                setup_clear_cpu_cap(X86_FEATURE_IBPB);
+                setup_clear_cpu_cap(X86_FEATURE_STIBP);
+                setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL);
+                setup_clear_cpu_cap(X86_FEATURE_INTEL_STIBP);
+        }
+
         /*
          * Atom erratum AAE44/AAF40/AAG38/AAH41:
          *