From 99158246208b82c0700d09a40d719bb56b32c607 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
Date: Wed, 31 Jan 2018 18:12:50 +0100
Subject: [PATCH] KVM: nVMX: preserve SECONDARY_EXEC_DESC without UMIP
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Git-commit: 99158246208b82c0700d09a40d719bb56b32c607
Patch-mainline: v4.16-rc4
References: bsc#1120716
L1 might want to use SECONDARY_EXEC_DESC, so we must not clear the VMCS
bit if UMIP is not being emulated.
We must still set the bit when emulating UMIP as the feature can be
passed to L2 where L0 will do the emulation and because L2 can change
CR4 without a VM exit, we should clear the bit if UMIP is disabled.
Fixes: 0367f205a3b7 ("KVM: vmx: add support for emulating UMIP")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Lin Ma <lma@suse.com>
---
arch/x86/kvm/vmx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 728fb1a16b75..31259ccb98ee 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4670,7 +4670,8 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL,
SECONDARY_EXEC_DESC);
hw_cr4 &= ~X86_CR4_UMIP;
- } else
+ } else if (!is_guest_mode(vcpu) ||
+ !nested_cpu_has2(get_vmcs12(vcpu), SECONDARY_EXEC_DESC))
vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL,
SECONDARY_EXEC_DESC);
--
2.16.2