From: Haiwei Li <lihai...@tencent.com>
Both 'kvm_send_ipi_mask_allbutself' and 'kvm_flush_tlb_others' are using
per-cpu __pv_cpu_mask. Init pv ipi ops only if the allocation succeeds and
check the cpumask in 'kvm_flush_tlb_others'.
Thanks to Vitaly Kuznetsov's tireless advice.
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
v3 -> v4:
* mov kvm_setup_pv_ipi to kvm_alloc_cpumask and get rid of kvm_apic_init
v4 -> v5:
* remove kvm_apic_init as an empty function
* define pv_ipi_supported() in !CONFIG_SMP case as 'false' to get rid of
'alloc' variable
* move kvm_setup_pv_ipi and define the implementation in CONFIG_SMP
arch/x86/kernel/kvm.c | 75 +++++++++++++++++++++++++------------------
1 file changed, 44 insertions(+), 31 deletions(-)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 42c6e0deff9e..2f2cc25d5078 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -547,16 +547,6 @@ static void kvm_send_ipi_mask_allbutself(const struct
cpumask *mask, int vector)
__send_ipi_mask(local_mask, vector);
}
-/*
- * Set the IPI entry points
- */
-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");
-}
-
static void kvm_smp_send_call_func_ipi(const struct cpumask *mask)
{
int cpu;
@@ -609,7 +599,24 @@ static int kvm_cpu_down_prepare(unsigned int cpu)
local_irq_enable();
return 0;
}
+#else
+static bool pv_ipi_supported(void)
+{
+ return false;
+}
+#endif
+
+/*
+ * Set the IPI entry points
+ */
+static void kvm_setup_pv_ipi(void)
+{
+#if defined(CONFIG_SMP)
+ apic->send_IPI_mask = kvm_send_ipi_mask;
+ apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+ pr_info("setup PV IPIs\n");
#endif
+}
static void kvm_flush_tlb_others(const struct cpumask *cpumask,
const struct flush_tlb_info *info)
@@ -619,6 +626,11 @@ 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
@@ -730,18 +742,9 @@ static uint32_t __init kvm_detect(void)
return kvm_cpuid_base();
}
-static void __init kvm_apic_init(void)
-{
-#if defined(CONFIG_SMP)
- if (pv_ipi_supported())
- kvm_setup_pv_ipi();
-#endif
-}
-
static void __init kvm_init_platform(void)
{
kvmclock_init();
- x86_platform.apic_post_init = kvm_apic_init;
}
const __initconst struct hypervisor_x86 x86_hyper_kvm = {
@@ -765,29 +768,39 @@ 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;
- bool alloc = false;
if (!kvm_para_available() || nopv)
return 0;
- if (pv_tlb_flush_supported())
- alloc = true;
-
-#if defined(CONFIG_SMP)
- if (pv_ipi_supported())
- alloc = true;
-#endif
-
- if (alloc)
+ if (pv_tlb_flush_supported() || pv_ipi_supported()) {
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 (pv_ipi_supported())
+ kvm_setup_pv_ipi();
return 0;
+
+zalloc_cpumask_fail:
+ kvm_free_cpumask();
+ return -ENOMEM;
}
arch_initcall(kvm_alloc_cpumask);
--
2.18.4
