KVM: vmx: we do rely on loading DR7 on entry

Currently, this works even if the bit is not in "min", because the bit is always
set in MSR_IA32_VMX_ENTRY_CTLS.  Mention it for the sake of documentation, and
to avoid surprises if we later switch to MSR_IA32_VMX_TRUE_ENTRY_CTLS.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -2871,7 +2871,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 		!(_vmexit_control & VM_EXIT_ACK_INTR_ON_EXIT))
 		_pin_based_exec_control &= ~PIN_BASED_POSTED_INTR;
 
-	min = 0;
+	min = VM_ENTRY_LOAD_DEBUG_CONTROLS;
 	opt = VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_BNDCFGS;
 	if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS,
 				&_vmentry_control) < 0)