If we have loaded a broken microcode at boot time, all the
speculation features will be blacklisted. Created a new
function for Intel CPUs to verify if we have a broken microcode
loaded or not and whitelist/blacklist features as needed.
This has to be done before get_cpu_cap because it uses these
black/white lists.
Signed-off-by: Mihai Carabas <mihai.cara...@oracle.com>
---
arch/x86/include/asm/microcode_intel.h | 1 +
arch/x86/kernel/cpu/intel.c | 28 ++++++++++++++++++++++++++++
arch/x86/kernel/cpu/microcode/intel.c | 5 ++++-
3 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/microcode_intel.h
b/arch/x86/include/asm/microcode_intel.h
index d85a07d..74c87cc 100644
--- a/arch/x86/include/asm/microcode_intel.h
+++ b/arch/x86/include/asm/microcode_intel.h
@@ -74,6 +74,7 @@ static inline u32 intel_get_microcode_revision(void)
extern void show_ucode_info_early(void);
extern int __init save_microcode_in_initrd_intel(void);
void reload_ucode_intel(void);
+void check_intel_bad_spectre_microcode(struct cpuinfo_x86 *c);
#else
static inline __init void load_ucode_intel_bsp(void) {}
static inline void load_ucode_intel_ap(void) {}
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index c25a67a..286168e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -170,6 +170,34 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
return false;
}
+/*
+ * check_intel_bad_spectre_microcode verifies if a valid microcode was
+ * loaded and whitelist/blacklist the features related to speculation control.
+ */
+void check_intel_bad_spectre_microcode(struct cpuinfo_x86 *c)
+{
+ int i;
+ unsigned int features[] = {
+ X86_FEATURE_IBRS,
+ X86_FEATURE_IBPB,
+ X86_FEATURE_STIBP,
+ X86_FEATURE_SPEC_CTRL,
+ X86_FEATURE_MSR_SPEC_CTRL,
+ X86_FEATURE_INTEL_STIBP,
+ X86_FEATURE_SSBD,
+ X86_FEATURE_SPEC_CTRL_SSBD
+ };
+
+ if (bad_spectre_microcode(c)) {
+ for (i = 0; i < ARRAY_SIZE(features); i++)
+ set_bit(features[i], (unsigned long *)cpu_caps_cleared);
+ } else {
+ for (i = 0; i < ARRAY_SIZE(features); i++)
+ clear_bit(features[i],
+ (unsigned long *)cpu_caps_cleared);
+ }
+}
+
static void early_init_intel(struct cpuinfo_x86 *c)
{
u64 misc_enable;
diff --git a/arch/x86/kernel/cpu/microcode/intel.c
b/arch/x86/kernel/cpu/microcode/intel.c
index 2ef4338..73a5a52 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -854,8 +854,11 @@ static enum ucode_state apply_microcode_intel(int cpu)
c->microcode = rev;
/* Update boot_cpu_data's revision too, if we're on the BSP: */
- if (bsp)
+ if (bsp) {
boot_cpu_data.microcode = rev;
+ /* Whitelist/blacklist speculation control features. */
+ check_intel_bad_spectre_microcode(c);
+ }
return ret;
}
--
1.8.3.1
