linux-kernel - Re: [PATCH v3 11/11] KVM: X86: Use common code for PV IPIs in linux guest

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Message-ID: <20240701093847.3f875868@jacob-builder>
Date: Mon, 1 Jul 2024 09:38:47 -0700
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: Xin Li <xin@...or.com>
Cc: X86 Kernel <x86@...nel.org>, Sean Christopherson <seanjc@...gle.com>,
 LKML <linux-kernel@...r.kernel.org>, Thomas Gleixner <tglx@...utronix.de>,
 Dave Hansen <dave.hansen@...el.com>, "H. Peter Anvin" <hpa@...or.com>, Ingo
 Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Xin Li
 <xin3.li@...el.com>, linux-perf-users@...r.kernel.org, Peter Zijlstra
 <peterz@...radead.org>, Paolo Bonzini <pbonzini@...hat.com>, Tony Luck
 <tony.luck@...el.com>, Andy Lutomirski <luto@...nel.org>, acme@...nel.org,
 kan.liang@...ux.intel.com, Andi Kleen <andi.kleen@...el.com>, "Mehta,
 Sohil" <sohil.mehta@...el.com>, Zeng Guang <guang.zeng@...el.com>,
 jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v3 11/11] KVM: X86: Use common code for PV IPIs in linux
 guest

On Sat, 29 Jun 2024 11:38:10 -0700, Xin Li <xin@...or.com> wrote:

> On 6/28/2024 1:18 PM, Jacob Pan wrote:
> > Paravirtual apic hooks to enable PV IPIs for KVM if the "send IPI"  
> 
> s/Paravirtual apic/Paravirtualize APIC/

Paravirtual APIC makes sense to me. This is also the same language used in
previous commits.

How about:

"The paravirtual APIC hooks in KVM, some of which are used for sending PV
IPIs, can reuse common code for ICR preparation. This shared code also
encompasses NMI-source reporting when in effect."

> > hypercall is available. Reuse common code for ICR preparation which
> > covers NMI-source reporting if in effect.  
> 
> I see a lot of "NMI source". Should we use "NMI-source" in all places?
Not really, here NMI-source is a compound modifier before noun "reporting".

For other places, hyphen(-) is not needed if it is just a noun. e.g.
"partial due to unknown NMI sources"

I will go through the patchset to make sure they are consistent.

> > 
> > Originally-by: Zeng Guang <guang.zeng@...el.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> > ---
> >   arch/x86/kernel/kvm.c | 10 +---------
> >   1 file changed, 1 insertion(+), 9 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> > index 263f8aed4e2c..a45d60aa0302 100644
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -516,15 +516,7 @@ static void __send_ipi_mask(const struct cpumask
> > *mask, int vector) 
> >   	local_irq_save(flags);
> >   
> > -	switch (vector) {
> > -	default:
> > -		icr = APIC_DM_FIXED | vector;
> > -		break;
> > -	case NMI_VECTOR:
> > -		icr = APIC_DM_NMI;
> > -		break;
> > -	}
> > -
> > +	icr = __prepare_ICR(0, vector, 0);
> >   	for_each_cpu(cpu, mask) {
> >   		apic_id = per_cpu(x86_cpu_to_apicid, cpu);
> >   		if (!ipi_bitmap) {  
> 

Thanks,

Jacob