linux-kernel - Re: [PATCH hyperv-next v5 06/11] arm64, x86: hyperv: Report the VTL the system boots in

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Message-ID: <Z84yyAqkqJ2ZyAd-@liuwe-devbox-ubuntu-v2.lamzopl0uupeniq2etz1fddiyg.xx.internal.cloudapp.net>
Date: Mon, 10 Mar 2025 00:31:04 +0000
From: Wei Liu <wei.liu@...nel.org>
To: Roman Kisel <romank@...ux.microsoft.com>
Cc: arnd@...db.de, bhelgaas@...gle.com, bp@...en8.de,
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Subject: Re: [PATCH hyperv-next v5 06/11] arm64, x86: hyperv: Report the VTL
 the system boots in

On Fri, Mar 07, 2025 at 02:02:58PM -0800, Roman Kisel wrote:
> The hyperv guest code might run in various Virtual Trust Levels.
> 
> Report the level when the kernel boots in the non-default (0)
> one.
> 
> Signed-off-by: Roman Kisel <romank@...ux.microsoft.com>
> ---
>  arch/arm64/hyperv/mshyperv.c | 2 ++
>  arch/x86/hyperv/hv_vtl.c     | 2 +-
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
> index a7db03f5413d..3bc16dbee758 100644
> --- a/arch/arm64/hyperv/mshyperv.c
> +++ b/arch/arm64/hyperv/mshyperv.c
> @@ -108,6 +108,8 @@ static int __init hyperv_init(void)
>  	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
>  		hv_get_partition_id();
>  	ms_hyperv.vtl = get_vtl();
> +	if (ms_hyperv.vtl > 0) /* non default VTL */

"non-default".

> +		pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);
>  
>  	ms_hyperv_late_init();
>  
> diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
> index 4e1b1e3b5658..c21bee7e8ff3 100644
> --- a/arch/x86/hyperv/hv_vtl.c
> +++ b/arch/x86/hyperv/hv_vtl.c
> @@ -24,7 +24,7 @@ static bool __init hv_vtl_msi_ext_dest_id(void)
>  
>  void __init hv_vtl_init_platform(void)
>  {
> -	pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
> +	pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);

Where isn't there a check for ms_hyperv.vtl > 0 here?

Please be consistent across different architectures.

>  
>  	x86_platform.realmode_reserve = x86_init_noop;
>  	x86_platform.realmode_init = x86_init_noop;
> -- 
> 2.43.0
> 
>