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

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Date:   Tue, 1 Sep 2020 19:41:37 +0800
From:   Haiwei Li <lihaiwei.kernel@...il.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Cc:     "hpa@...or.com" <hpa@...or.com>, "bp@...en8.de" <bp@...en8.de>,
        "mingo@...hat.com" <mingo@...hat.com>, tglx@...utronix.de,
        joro@...tes.org, jmattson@...gle.com,
        "wanpengli@...cent.com" <wanpengli@...cent.com>,
        vkuznets@...hat.com,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>
Subject: [PATCH] KVM: Check the allocation of pv cpu mask

From: Haiwei Li <lihaiwei@...cent.com>

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

Signed-off-by: Haiwei Li <lihaiwei@...cent.com>
---
  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