Ingo Molnar <mi...@kernel.org> writes:
> * Vitaly Kuznetsov <vkuzn...@redhat.com> wrote:
>
>> Hypervisor callback interrupts are only accounted on Xen/Hyper-V and we
>> detect hypervisor's type in early boot. There is no point in having
>> always-zero HYP: line on other hypervisors or bare metal.
>>
>> Suggested-by: Radim Krčmář <rkrc...@redhat.com>
>> Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
>> ---
>> arch/x86/kernel/irq.c | 13 +++++++++----
>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
>> index 88b36648..0c82064 100644
>> --- a/arch/x86/kernel/irq.c
>> +++ b/arch/x86/kernel/irq.c
>> @@ -18,6 +18,7 @@
>> #include <asm/mce.h>
>> #include <asm/hw_irq.h>
>> #include <asm/desc.h>
>> +#include <asm/hypervisor.h>
>>
>> #define CREATE_TRACE_POINTS
>> #include <asm/trace/irq_vectors.h>
>> @@ -139,10 +140,14 @@ int arch_show_interrupts(struct seq_file *p, int prec)
>> seq_puts(p, " Machine check polls\n");
>> #endif
>> #if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
>> - seq_printf(p, "%*s: ", prec, "HYP");
>> - for_each_online_cpu(j)
>> - seq_printf(p, "%10u ", irq_stats(j)->irq_hv_callback_count);
>> - seq_puts(p, " Hypervisor callback interrupts\n");
>> + if (x86_hyper == &x86_hyper_ms_hyperv ||
>> + x86_hyper == &x86_hyper_xen) {
>> + seq_printf(p, "%*s: ", prec, "HYP");
>> + for_each_online_cpu(j)
>> + seq_printf(p, "%10u ",
>> + irq_stats(j)->irq_hv_callback_count);
>> + seq_puts(p, " Hypervisor callback interrupts\n");
>> + }
>
> So I think we should simplify this to:
>
> if (x86_hyper) {
> ...
> }
>
> this will print the HYP line on hypervisors that don't use
> HYPERVISOR_CALLBACK_VECTOR, but it will make it a lot more self-maintaining,
> we
> won't accidentally skip this line on hypervisors that start using the
> callback
> IRQ.
I was under an impression KVM and Vmware don't use these hypervisor
callback irqs 'by desing' and even if one day they start using it
someone will have to put inc_irq_stat() somewhere.
If the goal is to avoid having x86_hyper_ms_hyperv/x86_hyper_xen in
irq.c we can follow Andrew's suggestion and add a flag
(use_callback_irqs?) to struct hypervisor_x86.
Thanks,
--
Vitaly
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