From 7c2bc303a035060c474aa931612c127cc5519c5b Mon Sep 17 00:00:00 2001 From: JP Kobryn Date: Fri, 27 Jun 2025 10:49:35 -0700 Subject: [PATCH] x86/mce: Make sure CMCI banks are cleared during shutdown on Intel commit 30ad231a5029bfa16e46ce868497b1a5cdd3c24d upstream. CMCI banks are not cleared during shutdown on Intel CPUs. As a side effect, when a kexec is performed, CPUs coming back online are unable to rediscover/claim these occupied banks which breaks MCE reporting. Clear the CPU ownership during shutdown via cmci_clear() so the banks can be reclaimed and MCE reporting will become functional once more. [ bp: Massage commit message. ] Reported-by: Aijay Adams Signed-off-by: JP Kobryn Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tony Luck Reviewed-by: Qiuxu Zhuo Cc: Link: https://lore.kernel.org/20250627174935.95194-1-inwardvessel@gmail.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mce/intel.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c index f2350967a898..4e893e583009 100644 --- a/arch/x86/kernel/cpu/mce/intel.c +++ b/arch/x86/kernel/cpu/mce/intel.c @@ -516,4 +516,5 @@ void mce_intel_feature_init(struct cpuinfo_x86 *c) void mce_intel_feature_clear(struct cpuinfo_x86 *c) { intel_clear_lmce(); + cmci_clear(); }