[PATCH v3] KVM: Check the allocation of pv cpu mask

[lihaiwei . kernel]

From: Haiwei Li <lihai...@tencent.com>

check the allocation of per-cpu __pv_cpu_mask.

Suggested-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Signed-off-by: Haiwei Li <lihai...@tencent.com>
---
v1 -> v2:
 * add CONFIG_SMP for kvm_send_ipi_mask_allbutself to prevent build error
v2 -> v3:
 * always check the allocation of __pv_cpu_mask in kvm_flush_tlb_others

 arch/x86/kernel/kvm.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 9663ba31347c..1e5da6db519c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -553,7 +553,6 @@ static void kvm_send_ipi_mask_allbutself(const struct 
cpumask *mask, int vector)
 static void kvm_setup_pv_ipi(void)
 {
        apic->send_IPI_mask = kvm_send_ipi_mask;
-       apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
        pr_info("setup PV IPIs\n");
 }
 
@@ -619,6 +618,11 @@ static void kvm_flush_tlb_others(const struct cpumask 
*cpumask,
        struct kvm_steal_time *src;
        struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
 
+       if (unlikely(!flushmask)) {
+               native_flush_tlb_others(cpumask, info);
+               return;
+       }
+
        cpumask_copy(flushmask, cpumask);
        /*
         * We have to call flush only on online vCPUs. And
@@ -765,6 +769,14 @@ static __init int activate_jump_labels(void)
 }
 arch_initcall(activate_jump_labels);
 
+static void kvm_free_cpumask(void)
+{
+       unsigned int cpu;
+
+       for_each_possible_cpu(cpu)
+               free_cpumask_var(per_cpu(__pv_cpu_mask, cpu));
+}
+
 static __init int kvm_alloc_cpumask(void)
 {
        int cpu;
@@ -783,11 +795,20 @@ static __init int kvm_alloc_cpumask(void)
 
        if (alloc)
                for_each_possible_cpu(cpu) {
-                       zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, 
cpu),
-                               GFP_KERNEL, cpu_to_node(cpu));
+                       if (!zalloc_cpumask_var_node(
+                               per_cpu_ptr(&__pv_cpu_mask, cpu),
+                               GFP_KERNEL, cpu_to_node(cpu)))
+                               goto zalloc_cpumask_fail;
                }
 
+#if defined(CONFIG_SMP)
+       apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+#endif
        return 0;
+
+zalloc_cpumask_fail:
+       kvm_free_cpumask();
+       return -ENOMEM;
 }
 arch_initcall(kvm_alloc_cpumask);
 
-- 
2.18.4