6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Christopherson <seanjc@xxxxxxxxxx>
[ Upstream commit 492077668fb453b8b16c842fcf3fafc2ebc190e9 ]
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: 8cc68c9c9e92 ("x86/CPU/AMD: Make sure EFER[AIBRSE] is set")
Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/Z1MkNofJjt7Oq0G6@xxxxxxxxxx
Closes: https://lore.kernel.org/all/20241205220604.GA2054199@thelio-3990X
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/x86/kernel/cpu/amd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 145c81c68394b..9413fb767c6a7 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1205,7 +1205,7 @@ 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);
if (!cpu_has(c, X86_FEATURE_HYPERVISOR) &&
cpu_has_amd_erratum(c, amd_erratum_1485))
--
2.43.0
