Commit-ID: 78f4e932f7760d965fb1569025d1576ab77557c5 Gitweb: https://git.kernel.org/tip/78f4e932f7760d965fb1569025d1576ab77557c5 Author: Borislav Petkov bp@suse.de AuthorDate: Thu, 13 Jun 2019 15:49:02 +0200 Committer: Borislav Petkov bp@suse.de CommitDate: Sat, 15 Jun 2019 10:00:29 +0200

x86/microcode, cpuhotplug: Add a microcode loader CPU hotplug callback

Adric Blake reported the following warning during suspend-resume:

Enabling non-boot CPUs ... x86: Booting SMP configuration: smpboot: Booting Node 0 Processor 1 APIC 0x2 unchecked MSR access error: WRMSR to 0x10f (tried to write 0x0000000000000000) \ at rIP: 0xffffffff8d267924 (native_write_msr+0x4/0x20) Call Trace: intel_set_tfa intel_pmu_cpu_starting ? x86_pmu_dead_cpu x86_pmu_starting_cpu cpuhp_invoke_callback ? _raw_spin_lock_irqsave notify_cpu_starting start_secondary secondary_startup_64 microcode: sig=0x806ea, pf=0x80, revision=0x96 microcode: updated to revision 0xb4, date = 2019-04-01 CPU1 is up

The MSR in question is MSR_TFA_RTM_FORCE_ABORT and that MSR is emulated by microcode. The log above shows that the microcode loader callback happens after the PMU restoration, leading to the conjecture that because the microcode hasn't been updated yet, that MSR is not present yet, leading to the #GP.

Add a microcode loader-specific hotplug vector which comes before the PERF vectors and thus executes earlier and makes sure the MSR is present.

Fixes: 400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort") Reported-by: Adric Blake promarbler14@gmail.com Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Thomas Gleixner tglx@linutronix.de Cc: Peter Zijlstra peterz@infradead.org Cc: stable@vger.kernel.org Cc: x86@kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=203637 --- arch/x86/kernel/cpu/microcode/core.c | 2 +- include/linux/cpuhotplug.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 70a04436380e..a813987b5552 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -872,7 +872,7 @@ int __init microcode_init(void) goto out_ucode_group;

register_syscore_ops(&mc_syscore_ops); - cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online", + cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:online", mc_cpu_online, mc_cpu_down_prep);

pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 6a381594608c..5c6062206760 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -101,6 +101,7 @@ enum cpuhp_state { CPUHP_AP_IRQ_BCM2836_STARTING, CPUHP_AP_IRQ_MIPS_GIC_STARTING, CPUHP_AP_ARM_MVEBU_COHERENCY, + CPUHP_AP_MICROCODE_LOADER, CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING, CPUHP_AP_PERF_X86_STARTING, CPUHP_AP_PERF_X86_AMD_IBS_STARTING,