[PATCH hyperv-next v6 06/11] arm64, x86: hyperv: Report the VTL the system boots in
From: Roman Kisel
Date: Fri Mar 14 2025 - 20:22:09 EST
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@xxxxxxxxxxxxxxxxxxx>
---
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 f251a08ada5b..ecbd2f5c955e 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -110,6 +110,8 @@ 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