RE: [RFC Patch v2 3/4] x86/Hyper-V: Not use auto-eoi when Secure AVIC is available

[Michael Kelley]

From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Friday, June 13, 2025 4:08 AM
> 
> From: Tianyu Lan <tiala@xxxxxxxxxxxxx>

Suggested Subject line:

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
> to force to write eoi register after handling
> interrupt.

Wording:

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@xxxxxxxxxxxxx>
> ---
>  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
>