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/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ff17deb..d167039 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -555,7 +555,7 @@
void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);
void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
- void (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
+ int (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
void (*set_efer)(struct kvm_vcpu *vcpu, u64 efer);
void (*get_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);