x86/kvm: Add output operand in vmx_handle_external_intr inline asm

Stacktool generates the following warning:
  stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup

By adding the stackpointer as an output operand, this patch ensures that a
stack frame is created when CONFIG_FRAME_POINTER is enabled for the inline
assmebly statement.

Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gleb@kernel.org
Cc: kvm@vger.kernel.org
Cc: live-patching@vger.kernel.org
Cc: pbonzini@redhat.com
Link: http://lkml.kernel.org/r/1453499078-9330-3-git-send-email-chris.j.arges@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6edbbce4deb5bad4fb38b8858c8093f8d5..e1535225bc1ddef9cf90a978dd7513150cef58f2 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8356,6 +8356,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
 static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 {
        u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
+       register void *__sp asm(_ASM_SP);
 
        /*
         * If external interrupt exists, IF bit is set in rflags/eflags on the
@@ -8388,8 +8389,9 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
                        "call *%[entry]\n\t"
                        :
 #ifdef CONFIG_X86_64
-                       [sp]"=&r"(tmp)
+                       [sp]"=&r"(tmp),
 #endif
+                       "+r"(__sp)
                        :
                        [entry]"r"(entry),
                        [ss]"i"(__KERNEL_DS),