linux-kernel - Re: [RFC PATCH V3 3/4] x86/Hyper-V: Don't use auto-eoi when Secure AVIC is available

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Message-ID: <CAMvTesBqMEs+9qYHLSko9L_YGi_nad4g1o1spOcFe1uqssRQag@mail.gmail.com>
Date: Sat, 26 Jul 2025 03:58:12 +0800
From: Tianyu Lan <ltykernel@...il.com>
To: Michael Kelley <mhklinux@...look.com>
Cc: "kys@...rosoft.com" <kys@...rosoft.com>, "haiyangz@...rosoft.com" <haiyangz@...rosoft.com>, 
	"wei.liu@...nel.org" <wei.liu@...nel.org>, "decui@...rosoft.com" <decui@...rosoft.com>, 
	"tglx@...utronix.de" <tglx@...utronix.de>, "mingo@...hat.com" <mingo@...hat.com>, "bp@...en8.de" <bp@...en8.de>, 
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>, "x86@...nel.org" <x86@...nel.org>, 
	"hpa@...or.com" <hpa@...or.com>, "arnd@...db.de" <arnd@...db.de>, 
	"Neeraj.Upadhyay@....com" <Neeraj.Upadhyay@....com>, Tianyu Lan <tiala@...rosoft.com>, 
	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>, 
	"linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH V3 3/4] x86/Hyper-V: Don't use auto-eoi when Secure
 AVIC is available

On Fri, Jul 25, 2025 at 7:34 AM Michael Kelley <mhklinux@...look.com> wrote:
>
> From: Tianyu Lan <ltykernel@...il.com> Sent: Wednesday, July 23, 2025 12:03 PM
> >
>
> I'm nit-picking, but the patch Subject: line prefix should be "x86/hyperv:"
> for consistency with past patches. Note that there's no capitalization
> or dash. I know not everyone is consistent on this if you look at the git log
> for mshyperv.c, but I try to flag it and encourage consistency.
>
> > Hyper-V doesn't support auto-eoi with Secure AVIC.
> > So set the HV_DEPRECATING_AEOI_RECOMMENDED flag
> > to force writing the EIO register after handling an interrupt.
> >
> > Signed-off-by: Tianyu Lan <tiala@...rosoft.com>
> > ---
> >  arch/x86/kernel/cpu/mshyperv.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> > index c78f860419d6..8f029650f16c 100644
> > --- a/arch/x86/kernel/cpu/mshyperv.c
> > +++ b/arch/x86/kernel/cpu/mshyperv.c
> > @@ -463,6 +463,8 @@ static void __init ms_hyperv_init_platform(void)
> >                ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
> >
> >       hv_identify_partition_type();
> > +     if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
> > +             ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;
> >
> >       if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {
> >               hv_nested = true;
> > --
> > 2.25.1
> >
>

Hi Michael:
  Thanks for your review. Will update.
-- 
Thanks
Tianyu Lan