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x86/mce: WARN once if IA32_FEAT_CTL MSR is left unlocked 

WARN if the IA32_FEAT_CTL MSR is somehow left unlocked now that CPU
initialization unconditionally locks the MSR.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-6-sean.j.christopherson@intel.com
This commit is contained in:
Sean Christopherson 2019-12-20 20:44:59 -08:00 committed by Borislav Petkov
parent 1db2a6e1e2
commit 6d527cebfa
1 changed files with 6 additions and 5 deletions
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11
arch/x86/kernel/cpu/mce/intel.c
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@ -116,14 +116,15 @@ static bool lmce_supported(void)
/*
* BIOS should indicate support for LMCE by setting bit 20 in
* IA32_FEAT_CTL without which touching MCG_EXT_CTL will generate a #GP
* fault.
* fault. The MSR must also be locked for LMCE_ENABLED to take effect.
* WARN if the MSR isn't locked as init_ia32_feat_ctl() unconditionally
* locks the MSR in the event that it wasn't already locked by BIOS.
*/
rdmsrl(MSR_IA32_FEAT_CTL, tmp);
if ((tmp & (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED)) ==
(FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED))
return true;
if (WARN_ON_ONCE(!(tmp & FEAT_CTL_LOCKED)))
return false;
return tmp & FEAT_CTL_LMCE_ENABLED;
}
bool mce_intel_cmci_poll(void)