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

From: Haiwei Li
Date: Tue Sep 01 2020 - 07:53:00 EST


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