Commit 49207766 authored by Sean Christopherson's avatar Sean Christopherson Committed by Ingo Molnar
Browse files

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



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: 8cc68c9c ("x86/CPU/AMD: Make sure EFER[AIBRSE] is set")
Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/Z1MkNofJjt7Oq0G6@google.com
Closes: https://lore.kernel.org/all/20241205220604.GA2054199@thelio-3990X
parent 9677be09

arch/x86/kernel/cpu/amd.c

+1 −1
Original line number Diff line number Diff line
@@ -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);