Re: [PATCH RESEND 1/1] X86: Handle Hyper-V vmbus interrupts asspecial hypervisor interrupts

From: Jan Beulich
Date: Thu Jan 24 2013 - 03:48:09 EST


>>> On 24.01.13 at 02:17, "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> wrote:
> @@ -69,6 +74,11 @@ static void __init ms_hyperv_init_platform(void)
> ms_hyperv.features, ms_hyperv.hints);
>
> clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
> +
> + /*
> + * Setup the IDT for hypervisor callback.
> + */
> + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);

Isn't doing this unconditionally here as problematic as the call to
clocksource_register_hz() turned out to be when Xen's Hyper-V
shim reacts to the CPUID inquiry above?

> @@ -77,3 +87,32 @@ const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
> .init_platform = ms_hyperv_init_platform,
> };
> EXPORT_SYMBOL(x86_hyper_ms_hyperv);
> +
> +static int vmbus_irq = -1;
> +static irq_handler_t vmbus_isr;
> +
> +void hv_register_vmbus_handler(int irq, irq_handler_t handler)
> +{
> + vmbus_irq = irq;
> + vmbus_isr = handler;
> +}
> +EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);
> +
> +void hyperv_vector_handler(struct pt_regs *regs)
> +{
> + struct pt_regs *old_regs = set_irq_regs(regs);
> + struct irq_desc *desc;
> +
> + irq_enter();
> +#ifdef CONFIG_X86
> + exit_idle();
> +#endif

This being in a file underneath arch/x86 - why the conditional?

Jan

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