linux-kernel - [PATCH 20/23] KVM: SVM: move VMLOAD/VMSAVE to C code

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Date:   Tue,  2 Mar 2021 14:33:40 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH 20/23] KVM: SVM: move VMLOAD/VMSAVE to C code

Thanks to the new macros that handle exception handling for SVM
instructions, it is easier to just do the VMLOAD/VMSAVE in C.
This is safe, as shown by the fact that the host reload is
already done outside the assembly source.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/svm.c     |  2 ++
 arch/x86/kvm/svm/vmenter.S | 14 +-------------
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1c62d3ec7e53..a0df44f6c239 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3719,7 +3719,9 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
 	} else {
 		struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu);
 
+		vmload(svm->vmcb_pa);
 		__svm_vcpu_run(svm->vmcb_pa, (unsigned long *)&vcpu->arch.regs);
+		vmsave(svm->vmcb_pa);
 
 		vmload(__sme_page_pa(sd->save_area));
 	}
diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 6feb8c08f45a..343108bf0f8c 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -79,12 +79,6 @@ SYM_FUNC_START(__svm_vcpu_run)
 
 	/* Enter guest mode */
 	sti
-1:	vmload %_ASM_AX
-	jmp 3f
-2:	cmpb $0, kvm_rebooting
-	jne 3f
-	ud2
-	_ASM_EXTABLE(1b, 2b)
 
 3:	vmrun %_ASM_AX
 	jmp 5f
@@ -93,13 +87,7 @@ SYM_FUNC_START(__svm_vcpu_run)
 	ud2
 	_ASM_EXTABLE(3b, 4b)
 
-5:	vmsave %_ASM_AX
-	jmp 7f
-6:	cmpb $0, kvm_rebooting
-	jne 7f
-	ud2
-	_ASM_EXTABLE(5b, 6b)
-7:
+5:
 	cli
 
 #ifdef CONFIG_RETPOLINE
-- 
2.26.2