From: Roman Kisel <rom...@linux.microsoft.com> Sent: Monday, April 14, 2025
3:47 PM
>
> 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 <rom...@linux.microsoft.com>
> ---
> arch/arm64/hyperv/mshyperv.c | 2 ++
> arch/x86/hyperv/hv_vtl.c | 7 ++++++-
> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
> index 43f422a7ef34..4fdc26ade1d7 100644
> --- a/arch/arm64/hyperv/mshyperv.c
> +++ b/arch/arm64/hyperv/mshyperv.c
> @@ -118,6 +118,8 @@ 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 */
> + 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 582fe820e29c..038c896fdd60 100644
> --- a/arch/x86/hyperv/hv_vtl.c
> +++ b/arch/x86/hyperv/hv_vtl.c
> @@ -55,7 +55,12 @@ static void __noreturn hv_vtl_restart(char __maybe_unused
> *cmd)
>
> void __init hv_vtl_init_platform(void)
> {
> - pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
> + /*
> + * This function is a no-op if the VTL mode is not enabled.
> + * If it is, this function runs if and only the kernel boots in
> + * VTL2 which the x86 hv initialization path makes sure of.
> + */
> + pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n",
> ms_hyperv.vtl);
>
> x86_platform.realmode_reserve = x86_init_noop;
> x86_platform.realmode_init = x86_init_noop;
> --
> 2.43.0
>
Reviewed-by: Michael Kelley <mhkli...@outlook.com>
