linux-kernel - [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line

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Date:   Fri, 26 Feb 2021 13:56:21 +0100
From:   Uros Bizjak <ubizjak@...il.com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Uros Bizjak <ubizjak@...il.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line

Avoid jump by moving exception fixups out of line.

Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Uros Bizjak <ubizjak@...il.com>
---
 arch/x86/kvm/svm/vmenter.S | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 343108bf0f8c..4fa17df123cd 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -80,15 +80,9 @@ SYM_FUNC_START(__svm_vcpu_run)
 	/* Enter guest mode */
 	sti
 
-3:	vmrun %_ASM_AX
-	jmp 5f
-4:	cmpb $0, kvm_rebooting
-	jne 5f
-	ud2
-	_ASM_EXTABLE(3b, 4b)
+1:	vmrun %_ASM_AX
 
-5:
-	cli
+2:	cli
 
 #ifdef CONFIG_RETPOLINE
 	/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
@@ -155,6 +149,13 @@ SYM_FUNC_START(__svm_vcpu_run)
 #endif
 	pop %_ASM_BP
 	ret
+
+3:	cmpb $0, kvm_rebooting
+	jne 2b
+	ud2
+
+	_ASM_EXTABLE(1b, 3b)
+
 SYM_FUNC_END(__svm_vcpu_run)
 
 /**
@@ -174,18 +175,15 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
 #endif
 	push %_ASM_BX
 
-	/* Enter guest mode */
+	/* Move @vmcb to RAX. */
 	mov %_ASM_ARG1, %_ASM_AX
+
+	/* Enter guest mode */
 	sti
 
 1:	vmrun %_ASM_AX
-	jmp 3f
-2:	cmpb $0, kvm_rebooting
-	jne 3f
-	ud2
-	_ASM_EXTABLE(1b, 2b)
 
-3:	cli
+2:	cli
 
 #ifdef CONFIG_RETPOLINE
 	/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
@@ -205,4 +203,11 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
 #endif
 	pop %_ASM_BP
 	ret
+
+3:	cmpb $0, kvm_rebooting
+	jne 2b
+	ud2
+
+	_ASM_EXTABLE(1b, 3b)
+
 SYM_FUNC_END(__svm_sev_es_vcpu_run)
-- 
2.29.2