On 20/9/3 18:39, Vitaly Kuznetsov wrote:
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.
.init.guest_late_init (kvm_guest_init()) is called before arch_initcall() and kvm_flush_tlb_others && kvm_send_ipi_mask_allbutself rely on __pv_cpu_mask. So, i can not put this assign in kvm_guest_init().
Have you checked that with this patch kvm_flush_tlb_others() is still being called?
yes. I add a printk and i get the log.
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.
I am sorry i don't really understand. Can you explain in more detail? Thx.
return 0; + +zalloc_cpumask_fail: + kvm_free_pv_cpu_mask(); + return -ENOMEM; } arch_initcall(kvm_alloc_cpumask); -- 2.18.4
