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

[Haiwei Li <lihaiwei.kernel@xxxxxxxxx>]

From: Haiwei Li <lihaiwei@xxxxxxxxxxx>

check the allocation of per-cpu __pv_cpu_mask. Initialize ops only when
successful.

Signed-off-by: Haiwei Li <lihaiwei@xxxxxxxxxxx>
---
 arch/x86/kernel/kvm.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 08320b0b2b27..a64b894eaac0 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -555,7 +555,6 @@ 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");
 }

@@ -654,7 +653,6 @@ static void __init kvm_guest_init(void)
 	}

 	if (pv_tlb_flush_supported()) {
-		pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
 		pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 		pr_info("KVM setup pv remote TLB flush\n");
 	}
@@ -767,6 +765,14 @@ static __init int activate_jump_labels(void)
 }
 arch_initcall(activate_jump_labels);

+static void kvm_free_pv_cpu_mask(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;
@@ -785,11 +791,20 @@ 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;
+			}
 		}

+	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
 	return 0;
+
+zalloc_cpumask_fail:
+	kvm_free_pv_cpu_mask();
+	return -ENOMEM;
 }
 arch_initcall(kvm_alloc_cpumask);

--
2.18.4