>>> On 30.01.13 at 01:51, "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> wrote:
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -14,10 +14,15 @@
> #include <linux/time.h>
> #include <linux/clocksource.h>
> #include <linux/module.h>
> +#include <linux/hardirq.h>
> +#include <linux/interrupt.h>
> #include <asm/processor.h>
> #include <asm/hypervisor.h>
> #include <asm/hyperv.h>
> #include <asm/mshyperv.h>
> +#include <asm/desc.h>
> +#include <asm/idle.h>
> +#include <asm/irq_regs.h>
>
> struct ms_hyperv_info ms_hyperv;
> EXPORT_SYMBOL_GPL(ms_hyperv);
> @@ -77,6 +82,12 @@ static void __init ms_hyperv_init_platform(void)
>
> if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
> clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
> +#if IS_ENABLED(CONFIG_HYPERV)
> + /*
> + * Setup the IDT for hypervisor callback.
> + */
> + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
> +#endif
> }
>
> const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
> @@ -85,3 +96,30 @@ 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();
> + exit_idle();
> +
> + desc = irq_to_desc(vmbus_irq);
> +
> + if (desc)
> + generic_handle_irq_desc(vmbus_irq, desc);
> +
> + irq_exit();
> + set_irq_regs(old_regs);
> +}
This function appears to be dead code when !CONFIG_HYPERV,
because ...
> --- a/arch/x86/kernel/entry_32.S
> +++ b/arch/x86/kernel/entry_32.S
> @@ -1046,11 +1046,18 @@ ENTRY(xen_failsafe_callback)
> _ASM_EXTABLE(4b,9b)
> ENDPROC(xen_failsafe_callback)
>
> -BUILD_INTERRUPT3(xen_hvm_callback_vector, XEN_HVM_EVTCHN_CALLBACK,
> +BUILD_INTERRUPT3(xen_hvm_callback_vector, HYPERVISOR_CALLBACK_VECTOR,
> xen_evtchn_do_upcall)
>
> #endif /* CONFIG_XEN */
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> +
> +BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR,
> + hyperv_vector_handler)
> +
> +#endif /* CONFIG_HYPERV */
> +
> #ifdef CONFIG_FUNCTION_TRACER
> #ifdef CONFIG_DYNAMIC_FTRACE
>
... the consumers here and below are conditional.
I also wonder why arch/x86/kernel/cpu/mshyperv.c is being built
at all when !CONFIG_HYPERV (which would eliminate the need
for the conditional the patch adds to ms_hyperv_init_platform()).
Jan
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index d5113c3..c1d01e6 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -1446,11 +1446,16 @@ ENTRY(xen_failsafe_callback)
> CFI_ENDPROC
> END(xen_failsafe_callback)
>
> -apicinterrupt XEN_HVM_EVTCHN_CALLBACK \
> +apicinterrupt HYPERVISOR_CALLBACK_VECTOR \
> xen_hvm_callback_vector xen_evtchn_do_upcall
>
> #endif /* CONFIG_XEN */
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> +apicinterrupt HYPERVISOR_CALLBACK_VECTOR \
> + hyperv_callback_vector hyperv_vector_handler
> +#endif /* CONFIG_HYPERV */
> +
> /*
> * Some functions should be protected against kprobes
> */
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