arm64, x86: hyperv: Report the VTL the system boots in

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@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250428210742.435282-7-romank@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250428210742.435282-7-romank@linux.microsoft.com>

diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index 43f422a7ef34259f43a5597f26e48e5450f4e347..4fdc26ade1d74372aa74853be0a2beb51ee86ab9 100644 (file)
--- 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 13242ed8ff16fe1893da740bafa51549ad4043ba..ac3d27a766d52af4179e9df757d19c58e358b763 100644 (file)
--- 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;