[PATCH v2 03/22] x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2

From: Josh Poimboeuf
Date: Wed Jul 17 2019 - 21:38:38 EST


Objtool reports the following:

arch/x86/kvm/vmx/vmenter.o: warning: objtool: vmx_vmenter()+0x14: call without frame pointer save/setup

But frame pointers are necessarily broken anyway, because
__vmx_vcpu_run() clobbers RBP with the guest's value before calling
vmx_vmenter(). So calling without a frame pointer doesn't make things
any worse.

Make objtool happy by changing the call to a UD2.

Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
v2: ud2 instead of kvm_spurious_fault() [Paolo]

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
arch/x86/kvm/vmx/vmenter.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index d4cb1945b2e3..4010d519eb8c 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -54,9 +54,9 @@ ENTRY(vmx_vmenter)
ret

3: cmpb $0, kvm_rebooting
- jne 4f
- call kvm_spurious_fault
-4: ret
+ je 4f
+ ret
+4: ud2

.pushsection .fixup, "ax"
5: jmp 3b
--
2.20.1