On Mon, Nov 18, 2019 at 07:12:26PM -0800, Sean Christopherson wrote:
WARN if the IA32_FEATURE_CONTROL MSR is somehow left unlocked now that CPU initialization unconditionally locks the MSR.
Reviewed-by: Borislav Petkov bp@suse.de Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com
arch/x86/kernel/cpu/mce/intel.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c index 3e5b29acd301..5abc55a67fce 100644 --- a/arch/x86/kernel/cpu/mce/intel.c +++ b/arch/x86/kernel/cpu/mce/intel.c @@ -119,11 +119,10 @@ static bool lmce_supported(void) * generate a #GP fault. */ rdmsrl(MSR_IA32_FEATURE_CONTROL, tmp);
- if ((tmp & (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED)) ==
(FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED))return true;
I'd add a prepending comment:
/* * FEAT_CTL_LOCKED should have been always set either by * BIOS before handover to the kernel or init_feature_control_msr(). */
- if (WARN_ON_ONCE(!(tmp & FEAT_CTL_LOCKED)))
return false;
- return false;
- return tmp & FEAT_CTL_LMCE_ENABLED;
} bool mce_intel_cmci_poll(void) -- 2.24.0
/Jarkko