From: Vitaly Kuznetsov vkuznets@redhat.com
[ Upstream commit baff59ccdc657d290be51b95b38ebe5de40036b4 ]
Allocating cpumask dynamically in zalloc_cpumask_var() is not ideal. Allocation is somewhat slow and can (in theory and when CPUMASK_OFFSTACK) fail. kvm_make_all_cpus_request_except() already disables preemption so we can use pre-allocated per-cpu cpumasks instead.
Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Reviewed-by: Sean Christopherson seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Message-Id: 20210903075141.403071-8-vkuznets@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Stable-dep-of: 2b0128127373 ("KVM: Register /dev/kvm as the _very_ last thing during initialization") Signed-off-by: Sasha Levin sashal@kernel.org --- virt/kvm/kvm_main.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d08dbf0be2fce..c60e88b0b24ec 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -157,6 +157,8 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); static unsigned long long kvm_createvm_count; static unsigned long long kvm_active_vms;
+static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask); + __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, unsigned long start, unsigned long end) { @@ -320,14 +322,15 @@ bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, struct kvm_vcpu *except) { struct kvm_vcpu *vcpu; - cpumask_var_t cpus; + struct cpumask *cpus; bool called; int i, me;
- zalloc_cpumask_var(&cpus, GFP_ATOMIC); - me = get_cpu();
+ cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + kvm_for_each_vcpu(i, vcpu, kvm) { if (vcpu == except) continue; @@ -337,7 +340,6 @@ bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); put_cpu();
- free_cpumask_var(cpus); return called; }
@@ -5637,9 +5639,17 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, goto out_free_3; }
+ for_each_possible_cpu(cpu) { + if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu), + GFP_KERNEL, cpu_to_node(cpu))) { + r = -ENOMEM; + goto out_free_4; + } + } + r = kvm_async_pf_init(); if (r) - goto out_free; + goto out_free_5;
kvm_chardev_ops.owner = module; kvm_vm_fops.owner = module; @@ -5665,7 +5675,10 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
out_unreg: kvm_async_pf_deinit(); -out_free: +out_free_5: + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); +out_free_4: kmem_cache_destroy(kvm_vcpu_cache); out_free_3: unregister_reboot_notifier(&kvm_reboot_notifier); @@ -5685,8 +5698,12 @@ EXPORT_SYMBOL_GPL(kvm_init);
void kvm_exit(void) { + int cpu; + debugfs_remove_recursive(kvm_debugfs_dir); misc_deregister(&kvm_dev); + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); kmem_cache_destroy(kvm_vcpu_cache); kvm_async_pf_deinit(); unregister_syscore_ops(&kvm_syscore_ops);