From f3e613e72f66226b3bea1046c1b864f67a3000a4 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 4 Nov 2021 18:22:39 +0000 Subject: x86/hyperv: Move required MSRs check to initial platform probing Explicitly check for MSR_HYPERCALL and MSR_VP_INDEX support when probing for running as a Hyper-V guest instead of waiting until hyperv_init() to detect the bogus configuration. Add messages to give the admin a heads up that they are likely running on a broken virtual machine setup. At best, silently disabling Hyper-V is confusing and difficult to debug, e.g. the kernel _says_ it's using all these fancy Hyper-V features, but always falls back to the native versions. At worst, the half baked setup will crash/hang the kernel. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20211104182239.1302956-3-seanjc@google.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 7d252a58fbe4..96eb7db31c8e 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -386,20 +386,13 @@ static void __init hv_get_partition_id(void) */ void __init hyperv_init(void) { - u64 guest_id, required_msrs; + u64 guest_id; union hv_x64_msr_hypercall_contents hypercall_msr; int cpuhp; if (x86_hyper_type != X86_HYPER_MS_HYPERV) return; - /* Absolutely required MSRs */ - required_msrs = HV_MSR_HYPERCALL_AVAILABLE | - HV_MSR_VP_INDEX_AVAILABLE; - - if ((ms_hyperv.features & required_msrs) != required_msrs) - return; - if (hv_common_init()) return; -- cgit v1.2.3