Re: [PATCH 38/44] KVM: Disable CPU hotplug during hardware enabling
From: Sean Christopherson <seanjc@google.com>
Date: 2022-11-17 15:21:20
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, linux-riscv, linux-s390, linuxppc-dev, lkml
On Thu, Nov 17, 2022, Huang, Kai wrote:
On Wed, 2022-11-16 at 17:11 +0000, Sean Christopherson wrote:quoted
static int kvm_x86_check_processor_compatibility(void) { int cpu = smp_processor_id(); struct cpuinfo_x86 *c = &cpu_data(cpu); /* * Compatibility checks are done when loading KVM and when enabling * hardware, e.g. during CPU hotplug, to ensure all online CPUs are * compatible, i.e. KVM should never perform a compatibility check on * an offline CPU. */ WARN_ON(!cpu_online(cpu));Looks good to me. Perhaps this also can be removed, though.
Hmm, it's a bit superfluous, but I think it could fire if KVM messed up CPU hotplug again, e.g. if the for_each_online_cpu() => IPI raced with CPU unplug.
And IMHO the removing of WARN_ON(!irq_disabled()) should be folded to the patch "[PATCH 37/44] KVM: Rename and move CPUHP_AP_KVM_STARTING to ONLINE section". Because moving from STARTING section to ONLINE section changes the IRQ status when the compatibility check is called.
Yep, that's what I have coded up, just smushed it all together here. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel