linux-kernel - [tip:core/urgent] x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious

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Date:   Thu, 18 Jul 2019 12:08:56 -0700
From:   tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, tglx@...utronix.de, pbonzini@...hat.com,
        mingo@...nel.org, linux-kernel@...r.kernel.org,
        jpoimboe@...hat.com, peterz@...radead.org
Subject: [tip:core/urgent] x86/kvm: Replace vmx_vmenter()'s call to
 kvm_spurious_fault() with UD2

Commit-ID:  19f2d8fa98644c7b78845b1d66abeae4e3d9dfa8
Gitweb:     https://git.kernel.org/tip/19f2d8fa98644c7b78845b1d66abeae4e3d9dfa8
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Wed, 17 Jul 2019 20:36:38 -0500
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 18 Jul 2019 21:01:03 +0200

x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2

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@...hat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Paolo Bonzini <pbonzini@...hat.com>
Link: https://lkml.kernel.org/r/9fc2216c9dc972f95bb65ce2966a682c6bda1cb0.1563413318.git.jpoimboe@redhat.com

---
 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