Re: [RFC PATCH 5/6] x86/Hyper-V: Not use auto-eoi when Secure AVIC is available

[Tianyu Lan]

On Thu, May 15, 2025 at 12:54 AM Michael Kelley <mhklinux@xxxxxxxxxxx> wrote:
>
> From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Tuesday, May 6, 2025 6:07 AM
> >
>
> For the patch Subject, use:
>
> x86/hyperv: Don't use auto-EOI when Secure AVIC is available
>
> > Hyper-V doesn't support auto-eoi with Secure AVIC.
> > So Enable HV_DEPRECATING_AEOI_RECOMMENDED flag
>
> s/Enable/enable/
> > to force to write eoi register after handling interrupt.
>
> "to force writing the EOI register after handling an interrupt."
>
> >
> > Signed-off-by: Tianyu Lan <tiala@xxxxxxxxxxxxx>
> > ---
> >  arch/x86/kernel/cpu/mshyperv.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> > index 3e2533954675..fbe45b5e9790 100644
> > --- a/arch/x86/kernel/cpu/mshyperv.c
> > +++ b/arch/x86/kernel/cpu/mshyperv.c
> > @@ -463,6 +463,9 @@ static void __init ms_hyperv_init_platform(void)
> >
> >       hv_identify_partition_type();
> >
> > +     if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
> > +             ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;
> > +
>
> Shouldn't Hyper-V already be setting this flag if it is offering Secure AVIC
> to guests? I guess it doesn't hurt to do this in the Linux code, but it seems
> like it should be Hyper-V's responsibility.
>

OK. I will double check from OpenHCL side.



-- 
Thanks
Tianyu Lan