KVM: nVMX: Allow setting the VMXE bit in CR4
This patch allows the guest to enable the VMXE bit in CR4, which is a
prerequisite to running VMXON.
Whether to allow setting the VMXE bit now depends on the architecture (svm
or vmx), so its checking has moved to kvm_x86_ops->set_cr4(). This function
now returns an int: If kvm_x86_ops->set_cr4() returns 1, __kvm_set_cr4()
will also return 1, and this will cause kvm_set_cr4() will throw a #GP.
Turning on the VMXE bit is allowed only when the nested VMX feature is
enabled, and turning it off is forbidden after a vmxon.
Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d88de56..460932b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -615,11 +615,9 @@
kvm_read_cr3(vcpu)))
return 1;
- if (cr4 & X86_CR4_VMXE)
+ if (kvm_x86_ops->set_cr4(vcpu, cr4))
return 1;
- kvm_x86_ops->set_cr4(vcpu, cr4);
-
if ((cr4 ^ old_cr4) & pdptr_bits)
kvm_mmu_reset_context(vcpu);