KVM: nVMX: Always enable TSC scaling for L2 when it was enabled for L1

Windows 10/11 guests with Hyper-V role (WSL2) enabled are observed to
hang upon boot or shortly after when a non-default TSC frequency was
set for L1. The issue is observed on a host where TSC scaling is
supported. The problem appears to be that Windows doesn't use TSC
frequency for its guests even when the feature is advertised and KVM
filters SECONDARY_EXEC_TSC_SCALING out when creating L2 controls from
L1's. This leads to L2 running with the default frequency (matching
host's) while L1 is running with an altered one.

Keep SECONDARY_EXEC_TSC_SCALING in secondary exec controls for L2 when
it was set for L1. TSC_MULTIPLIER is already correctly computed and
written by prepare_vmcs02().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220712135009.952805-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f5cb18e00e789259b591c677ad5ddac18a3ce621..67d6298376727c19655b0f76c58cadf8a9d9b6c6 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2278,7 +2278,6 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
                                  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
                                  SECONDARY_EXEC_APIC_REGISTER_VIRT |
                                  SECONDARY_EXEC_ENABLE_VMFUNC |
-                                 SECONDARY_EXEC_TSC_SCALING |
                                  SECONDARY_EXEC_DESC);
 
                if (nested_cpu_has(vmcs12,