[PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley]

Some hypervisor interrupts (such as for Hyper-V VMbus and Hyper-V timers)
have hardcoded interrupt vectors on x86 and don't have Linux IRQs assigned.
These interrupts are shown in /proc/interrupts, but are not reported in
the first field of the "intr" line in /proc/stat because the x86 version
of arch_irq_stat_cpu() doesn't include them.

Fix this by adding code to arch_irq_stat_cpu() to include these interrupts,
similar to existing interrupts that don't have Linux IRQs.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/x86/kernel/irq.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 766ffe3..9f668d2 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 #ifdef CONFIG_X86_MCE_THRESHOLD
 	sum += irq_stats(cpu)->irq_threshold_count;
 #endif
+#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
+	sum += irq_stats(cpu)->irq_hv_callback_count;
+#endif
+#if IS_ENABLED(CONFIG_HYPERV)
+	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
+	sum += irq_stats(cpu)->hyperv_stimer0_count;
+#endif
 #ifdef CONFIG_X86_MCE
 	sum += per_cpu(mce_exception_count, cpu);
 	sum += per_cpu(mce_poll_count, cpu);
-- 
1.8.3.1

RE: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley (LINUX)]

From: Michael Kelley (LINUX) <mikelley@microsoft.com> Sent: Monday, February 27, 2023 10:46 AM
> 
> Some hypervisor interrupts (such as for Hyper-V VMbus and Hyper-V timers)
> have hardcoded interrupt vectors on x86 and don't have Linux IRQs assigned.
> These interrupts are shown in /proc/interrupts, but are not reported in
> the first field of the "intr" line in /proc/stat because the x86 version
> of arch_irq_stat_cpu() doesn't include them.
> 
> Fix this by adding code to arch_irq_stat_cpu() to include these interrupts,
> similar to existing interrupts that don't have Linux IRQs.
> 
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>

Gentle ping.  Any comments on this patch?  Seems pretty
straightforward to me ....

Michael

> ---
>  arch/x86/kernel/irq.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> index 766ffe3..9f668d2 100644
> --- a/arch/x86/kernel/irq.c
> +++ b/arch/x86/kernel/irq.c
> @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
>  #ifdef CONFIG_X86_MCE_THRESHOLD
>  	sum += irq_stats(cpu)->irq_threshold_count;
>  #endif
> +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> +	sum += irq_stats(cpu)->irq_hv_callback_count;
> +#endif
> +#if IS_ENABLED(CONFIG_HYPERV)
> +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> +#endif
>  #ifdef CONFIG_X86_MCE
>  	sum += per_cpu(mce_exception_count, cpu);
>  	sum += per_cpu(mce_poll_count, cpu);
> --
> 1.8.3.1

Re: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Dave Hansen]

On 2/27/23 10:46, Michael Kelley wrote:
> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> index 766ffe3..9f668d2 100644
> --- a/arch/x86/kernel/irq.c
> +++ b/arch/x86/kernel/irq.c
> @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
>  #ifdef CONFIG_X86_MCE_THRESHOLD
>  	sum += irq_stats(cpu)->irq_threshold_count;
>  #endif
> +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> +	sum += irq_stats(cpu)->irq_hv_callback_count;
> +#endif
> +#if IS_ENABLED(CONFIG_HYPERV)
> +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> +#endif
>  #ifdef CONFIG_X86_MCE
>  	sum += per_cpu(mce_exception_count, cpu);
>  	sum += per_cpu(mce_poll_count, cpu);

This seems fine, especially since arch_show_interrupts() has them.  But,
what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
difference I'm missing?  Why not just be consistent with the other code
and use a plain #ifdef for both?

RE: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley (LINUX)]

From: Dave Hansen <dave.hansen@intel.com> Sent: Wednesday, March 22, 2023 11:07 AM
> 
> On 2/27/23 10:46, Michael Kelley wrote:
> > diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> > index 766ffe3..9f668d2 100644
> > --- a/arch/x86/kernel/irq.c
> > +++ b/arch/x86/kernel/irq.c
> > @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
> >  #ifdef CONFIG_X86_MCE_THRESHOLD
> >  	sum += irq_stats(cpu)->irq_threshold_count;
> >  #endif
> > +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> > +	sum += irq_stats(cpu)->irq_hv_callback_count;
> > +#endif
> > +#if IS_ENABLED(CONFIG_HYPERV)
> > +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> > +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> > +#endif
> >  #ifdef CONFIG_X86_MCE
> >  	sum += per_cpu(mce_exception_count, cpu);
> >  	sum += per_cpu(mce_poll_count, cpu);
> 
> This seems fine, especially since arch_show_interrupts() has them.  But,
> what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
> difference I'm missing?  Why not just be consistent with the other code
> and use a plain #ifdef for both?

I'm following the coding pattern in arch_show_interrupts(), in irq_cpustat_t,
and most other places that test CONFIG_HYPERV.   Maybe all those existing
cases are a mis-application of Documentation/process/coding-style.rst
Section 21, which prefers "if (IS_ENABLED(CONFIG_HYPERV))" over
"#ifdef CONFIG_HYPERV".  "#if IS_ENABLED()" is not the same as
"if (IS_ENABLED())".  :-)

 Net, I don't have a strong preference either way.  

Michael

Re: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Sean Christopherson]

On Wed, Mar 22, 2023, Michael Kelley (LINUX) wrote:
> From: Dave Hansen <dave.hansen@intel.com> Sent: Wednesday, March 22, 2023 11:07 AM
> > 
> > On 2/27/23 10:46, Michael Kelley wrote:
> > > diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> > > index 766ffe3..9f668d2 100644
> > > --- a/arch/x86/kernel/irq.c
> > > +++ b/arch/x86/kernel/irq.c
> > > @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
> > >  #ifdef CONFIG_X86_MCE_THRESHOLD
> > >  	sum += irq_stats(cpu)->irq_threshold_count;
> > >  #endif
> > > +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> > > +	sum += irq_stats(cpu)->irq_hv_callback_count;
> > > +#endif
> > > +#if IS_ENABLED(CONFIG_HYPERV)
> > > +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> > > +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> > > +#endif
> > >  #ifdef CONFIG_X86_MCE
> > >  	sum += per_cpu(mce_exception_count, cpu);
> > >  	sum += per_cpu(mce_poll_count, cpu);
> > 
> > This seems fine, especially since arch_show_interrupts() has them.  But,
> > what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
> > difference I'm missing?  Why not just be consistent with the other code
> > and use a plain #ifdef for both?
> 
> I'm following the coding pattern in arch_show_interrupts(), in irq_cpustat_t,
> and most other places that test CONFIG_HYPERV.   Maybe all those existing
> cases are a mis-application of Documentation/process/coding-style.rst
> Section 21, which prefers "if (IS_ENABLED(CONFIG_HYPERV))" over
> "#ifdef CONFIG_HYPERV".  "#if IS_ENABLED()" is not the same as
> "if (IS_ENABLED())".  :-)
> 
>  Net, I don't have a strong preference either way.

Using IS_ENABLED() is mandatory because CONFIG_HYPERV is a tri-state, i.e. can
be a module and thus #define CONFIG_HYPER_MODULE instead of CONFIG_HYPERV.

RE: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley (LINUX)]

From: Sean Christopherson <seanjc@google.com> Sent: Wednesday, March 22, 2023 6:27 PM
> 
> On Wed, Mar 22, 2023, Michael Kelley (LINUX) wrote:
> > From: Dave Hansen <dave.hansen@intel.com> Sent: Wednesday, March 22, 2023
> 11:07 AM
> > >
> > > On 2/27/23 10:46, Michael Kelley wrote:
> > > > diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> > > > index 766ffe3..9f668d2 100644
> > > > --- a/arch/x86/kernel/irq.c
> > > > +++ b/arch/x86/kernel/irq.c
> > > > @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
> > > >  #ifdef CONFIG_X86_MCE_THRESHOLD
> > > >  	sum += irq_stats(cpu)->irq_threshold_count;
> > > >  #endif
> > > > +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> > > > +	sum += irq_stats(cpu)->irq_hv_callback_count;
> > > > +#endif
> > > > +#if IS_ENABLED(CONFIG_HYPERV)
> > > > +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> > > > +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> > > > +#endif
> > > >  #ifdef CONFIG_X86_MCE
> > > >  	sum += per_cpu(mce_exception_count, cpu);
> > > >  	sum += per_cpu(mce_poll_count, cpu);
> > >
> > > This seems fine, especially since arch_show_interrupts() has them.  But,
> > > what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
> > > difference I'm missing?  Why not just be consistent with the other code
> > > and use a plain #ifdef for both?
> >
> > I'm following the coding pattern in arch_show_interrupts(), in irq_cpustat_t,
> > and most other places that test CONFIG_HYPERV.   Maybe all those existing
> > cases are a mis-application of Documentation/process/coding-style.rst
> > Section 21, which prefers "if (IS_ENABLED(CONFIG_HYPERV))" over
> > "#ifdef CONFIG_HYPERV".  "#if IS_ENABLED()" is not the same as
> > "if (IS_ENABLED())".  :-)
> >
> >  Net, I don't have a strong preference either way.
> 
> Using IS_ENABLED() is mandatory because CONFIG_HYPERV is a tri-state, i.e. can
> be a module and thus #define CONFIG_HYPER_MODULE instead of CONFIG_HYPERV.

Ah, right.  Thanks.

Michael

RE: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley (LINUX)]

From: Michael Kelley (LINUX) <mikelley@microsoft.com> Sent: Thursday, March 23, 2023 10:36 AM
> 
> From: Sean Christopherson <seanjc@google.com> Sent: Wednesday, March 22, 2023
> 6:27 PM
> >
> > On Wed, Mar 22, 2023, Michael Kelley (LINUX) wrote:
> > > From: Dave Hansen <dave.hansen@intel.com> Sent: Wednesday, March 22, 2023
> > 11:07 AM
> > > >
> > > > On 2/27/23 10:46, Michael Kelley wrote:
> > > > > diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> > > > > index 766ffe3..9f668d2 100644
> > > > > --- a/arch/x86/kernel/irq.c
> > > > > +++ b/arch/x86/kernel/irq.c
> > > > > @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
> > > > >  #ifdef CONFIG_X86_MCE_THRESHOLD
> > > > >  	sum += irq_stats(cpu)->irq_threshold_count;
> > > > >  #endif
> > > > > +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> > > > > +	sum += irq_stats(cpu)->irq_hv_callback_count;
> > > > > +#endif
> > > > > +#if IS_ENABLED(CONFIG_HYPERV)
> > > > > +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> > > > > +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> > > > > +#endif
> > > > >  #ifdef CONFIG_X86_MCE
> > > > >  	sum += per_cpu(mce_exception_count, cpu);
> > > > >  	sum += per_cpu(mce_poll_count, cpu);
> > > >
> > > > This seems fine, especially since arch_show_interrupts() has them.  But,
> > > > what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
> > > > difference I'm missing?  Why not just be consistent with the other code
> > > > and use a plain #ifdef for both?
> > >
> > > I'm following the coding pattern in arch_show_interrupts(), in irq_cpustat_t,
> > > and most other places that test CONFIG_HYPERV.   Maybe all those existing
> > > cases are a mis-application of Documentation/process/coding-style.rst
> > > Section 21, which prefers "if (IS_ENABLED(CONFIG_HYPERV))" over
> > > "#ifdef CONFIG_HYPERV".  "#if IS_ENABLED()" is not the same as
> > > "if (IS_ENABLED())".  :-)
> > >
> > >  Net, I don't have a strong preference either way.
> >
> > Using IS_ENABLED() is mandatory because CONFIG_HYPERV is a tri-state, i.e. can
> > be a module and thus #define CONFIG_HYPER_MODULE instead of CONFIG_HYPERV.
> 
> Ah, right.  Thanks.
> 

x86 maintainers:   Any issues with picking up this patch for the 6.4 merge window?

Michael

RE: [PATCH 1/1] x86/irq: Add hardcoded hypervisor interrupts to /proc/stat

[Michael Kelley (LINUX)]

From: Dave Hansen <dave.hansen@intel.com> Sent: Wednesday, March 22, 2023 11:07 AM
> 
> On 2/27/23 10:46, Michael Kelley wrote:
> > diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
> > index 766ffe3..9f668d2 100644
> > --- a/arch/x86/kernel/irq.c
> > +++ b/arch/x86/kernel/irq.c
> > @@ -211,6 +211,13 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
> >  #ifdef CONFIG_X86_MCE_THRESHOLD
> >  	sum += irq_stats(cpu)->irq_threshold_count;
> >  #endif
> > +#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
> > +	sum += irq_stats(cpu)->irq_hv_callback_count;
> > +#endif
> > +#if IS_ENABLED(CONFIG_HYPERV)
> > +	sum += irq_stats(cpu)->irq_hv_reenlightenment_count;
> > +	sum += irq_stats(cpu)->hyperv_stimer0_count;
> > +#endif
> >  #ifdef CONFIG_X86_MCE
> >  	sum += per_cpu(mce_exception_count, cpu);
> >  	sum += per_cpu(mce_poll_count, cpu);
> 
> This seems fine, especially since arch_show_interrupts() has them.  But,
> what's with the "#if IS_ENABLED" versus the plain #ifdef?  Is there some
> difference I'm missing?  Why not just be consistent with the other code
> and use a plain #ifdef for both?

Dave --

With Sean's explanation for #if IS_ENABLED, are you OK with giving this
an ACK as an x86 maintainer?   This patch has been hanging around for a
while now ...

Michael