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Subject[PATCH AUTOSEL 5.18 53/54] KVM: nVMX: Always enable TSC scaling for L2 when it was enabled for L1
Date
From: Vitaly Kuznetsov <vkuznets@redhat.com>

[ Upstream commit 99482726452bdf8be9325199022b17fa6d7d58fe ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/vmx/nested.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 28ccf25c4124..223de8e0dd5f 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2279,7 +2279,6 @@ 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,
--
2.35.1
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