linux-kernel - [PATCH 7/8] KVM: SVM: Create a stack frame in __svm_sev_es_vcpu

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Message-ID: <20240223204233.3337324-8-seanjc@google.com>
Date: Fri, 23 Feb 2024 12:42:32 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Tom Lendacky <thomas.lendacky@....com>, Michael Roth <michael.roth@....com>, 
	Alexey Kardashevskiy <aik@....com>
Subject: [PATCH 7/8] KVM: SVM: Create a stack frame in __svm_sev_es_vcpu_run()

Now that KVM uses the host save area to context switch RBP, i.e.
preserves RBP for the entirety of __svm_sev_es_vcpu_run(), create a stack
frame using the standared FRAME_{BEGIN,END} macros.

Note, __svm_sev_es_vcpu_run() is subtly not a leaf function as it can call
into ibpb_feature() via UNTRAIN_RET_VM.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/vmenter.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 48cdba47622c..5461c23ee762 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -3,6 +3,7 @@
 #include <asm/asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/bitsperlong.h>
+#include <asm/frame.h>
 #include <asm/kvm_vcpu_regs.h>
 #include <asm/nospec-branch.h>
 #include "kvm-asm-offsets.h"
@@ -312,6 +313,8 @@ SYM_FUNC_END(__svm_vcpu_run)
  * @spec_ctrl_intercepted: bool
  */
 SYM_FUNC_START(__svm_sev_es_vcpu_run)
+	FRAME_BEGIN
+
 	/*
 	 * Save non-volatile (callee-saved) registers to the host save area.
 	 * Except for RAX and RSP, all GPRs are restored on #VMEXIT, but not
@@ -362,6 +365,7 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
 	 */
 	UNTRAIN_RET_VM
 
+	FRAME_END
 	RET
 
 	RESTORE_GUEST_SPEC_CTRL_BODY
-- 
2.44.0.rc0.258.g7320e95886-goog