diff options
Diffstat (limited to 'arch/x86/kernel/irq.c')
| -rw-r--r-- | arch/x86/kernel/irq.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index e28f6a5d14f1..e3c35668c7c5 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -182,6 +182,12 @@ int arch_show_interrupts(struct seq_file *p, int prec) irq_stats(j)->kvm_posted_intr_wakeup_ipis); seq_puts(p, " Posted-interrupt wakeup event\n"); #endif +#ifdef CONFIG_X86_USER_INTERRUPTS + seq_printf(p, "%*s: ", prec, "UIS"); + for_each_online_cpu(j) + seq_printf(p, "%10u ", irq_stats(j)->uintr_spurious_count); + seq_puts(p, " User-interrupt spurious event\n"); +#endif return 0; } @@ -325,6 +331,33 @@ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_kvm_posted_intr_nested_ipi) } #endif +#ifdef CONFIG_X86_USER_INTERRUPTS +/* + * Handler for UINTR_NOTIFICATION_VECTOR. + * + * The notification vector is used by the cpu to detect a User Interrupt. In + * the typical usage, the cpu would handle this interrupt and clear the local + * apic. + * + * However, it is possible that the kernel might receive this vector. This can + * happen if the receiver thread was running when the interrupt was sent but it + * got scheduled out before the interrupt was delivered. The kernel doesn't + * need to do anything other than clearing the local APIC. A pending user + * interrupt is always saved in the receiver's UPID which can be referenced + * when the receiver gets scheduled back. + * + * If the kernel receives a storm of these, it could mean an issue with the + * kernel's saving and restoring of the User Interrupt MSR state; Specifically, + * the notification vector bits in the IA32_UINTR_MISC_MSR. + */ +DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_uintr_spurious_interrupt) +{ + /* TODO: Add entry-exit tracepoints */ + ack_APIC_irq(); + inc_irq_stat(uintr_spurious_count); +} +#endif + #ifdef CONFIG_HOTPLUG_CPU /* A cpu has been removed from cpu_online_mask. Reset irq affinities. */ |