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x86/CPU/AMD: WARN when setting EFER.AUTOIBRS if and only if the WRMSR fails

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When ensuring EFER.AUTOIBRS is set, WARN only on a negative return code
from msr_set_bit(), as '1' is used to indicate the WRMSR was successful
('0' indicates the MSR bit was already set).

Fixes: 8cc68c9c9e ("x86/CPU/AMD: Make sure EFER[AIBRSE] is set")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/Z1MkNofJjt7Oq0G6@google.com
Closes: https://lore.kernel.org/all/20241205220604.GA2054199@thelio-3990X
This commit is contained in:
Sean Christopherson 2024-12-06 08:20:06 -08:00 committed by Ingo Molnar
parent 9677be09e5
commit 492077668f
1 changed files with 1 additions and 1 deletions
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arch/x86/kernel/cpu/amd.c
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@ -1065,7 +1065,7 @@ static void init_amd(struct cpuinfo_x86 *c)
*/
if (spectre_v2_in_eibrs_mode(spectre_v2_enabled) &&
cpu_has(c, X86_FEATURE_AUTOIBRS))
WARN_ON_ONCE(msr_set_bit(MSR_EFER, _EFER_AUTOIBRS));
WARN_ON_ONCE(msr_set_bit(MSR_EFER, _EFER_AUTOIBRS) < 0);
/* AMD CPUs don't need fencing after x2APIC/TSC_DEADLINE MSR writes. */
clear_cpu_cap(c, X86_FEATURE_APIC_MSRS_FENCE);