Haiwei Li <lihaiwei.kernel@xxxxxxxxx> writes:
> 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 | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 08320b0b2b27..d3c062e551d7 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 +791,21 @@ 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
> + pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
This is too late I'm afraid. If I'm not mistaken PV patching happens
earlier, so .init.guest_late_init (kvm_guest_init()) is good and
arch_initcall() is bad.
Have you checked that with this patch kvm_flush_tlb_others() is still
being called?
Actually, there is no need to assign kvm_flush_tlb_others() so late. We
can always check if __pv_cpu_mask was allocated and revert back to the
architectural path if not.
> return 0;
> +
> +zalloc_cpumask_fail:
> + kvm_free_pv_cpu_mask();
> + return -ENOMEM;
> }
> arch_initcall(kvm_alloc_cpumask);
>
> --
> 2.18.4
>
--
Vitaly
