linux-kernel - [PATCH v2 2/3] kvm: x86: Refactor kvm_emulate

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Date:   Thu,  9 Sep 2021 19:55:24 +0800
From:   Hou Wenlong <houwenlong93@...ux.alibaba.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        "H. Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND
        64-BIT))
Subject: [PATCH v2 2/3] kvm: x86: Refactor kvm_emulate_hypercall() to no skip instruction

Refactor kvm_emulate_hypercall() to no skip instruction, it can
be used in next patch for emulating hypercall in instruction
emulation.

Signed-off-by: Hou Wenlong <houwenlong93@...ux.alibaba.com>
---
 arch/x86/kvm/x86.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4e2836b94a01..b8d799e1c57c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8636,17 +8636,11 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu)
 	return kvm_skip_emulated_instruction(vcpu);
 }
 
-int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
+static int kvm_emulate_hypercall_noskip(struct kvm_vcpu *vcpu)
 {
 	unsigned long nr, a0, a1, a2, a3, ret;
 	int op_64_bit;
 
-	if (kvm_xen_hypercall_enabled(vcpu->kvm))
-		return kvm_xen_hypercall(vcpu);
-
-	if (kvm_hv_hypercall_enabled(vcpu))
-		return kvm_hv_hypercall(vcpu);
-
 	nr = kvm_rax_read(vcpu);
 	a0 = kvm_rbx_read(vcpu);
 	a1 = kvm_rcx_read(vcpu);
@@ -8664,11 +8658,6 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 		a3 &= 0xFFFFFFFF;
 	}
 
-	if (static_call(kvm_x86_get_cpl)(vcpu) != 0) {
-		static_call(kvm_x86_handle_hypercall_fail)(vcpu);
-		return 1;
-	}
-
 	ret = -KVM_ENOSYS;
 
 	switch (nr) {
@@ -8733,7 +8722,28 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
 	kvm_rax_write(vcpu, ret);
 
 	++vcpu->stat.hypercalls;
-	return kvm_skip_emulated_instruction(vcpu);
+	return 1;
+}
+
+int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	if (kvm_xen_hypercall_enabled(vcpu->kvm))
+		return kvm_xen_hypercall(vcpu);
+
+	if (kvm_hv_hypercall_enabled(vcpu))
+		return kvm_hv_hypercall(vcpu);
+
+	if (static_call(kvm_x86_get_cpl)(vcpu) != 0) {
+		static_call(kvm_x86_handle_hypercall_fail)(vcpu);
+		return 1;
+	}
+
+	ret = kvm_emulate_hypercall_noskip(vcpu);
+	if (ret)
+		return kvm_skip_emulated_instruction(vcpu);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);
 
-- 
2.31.1