linux-kernel - [PATCH 5/6] KVM: SVM: pass a proper reason in kvm_emulate

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Date:   Mon, 12 Apr 2021 14:09:36 +0100
From:   David Edmondson <david.edmondson@...cle.com>
To:     linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Joerg Roedel <joro@...tes.org>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>,
        Jim Mattson <jmattson@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Joao Martins <joao.m.martins@...cle.com>,
        David Edmondson <david.edmondson@...cle.com>
Subject: [PATCH 5/6] KVM: SVM: pass a proper reason in kvm_emulate_instruction()

From: Joao Martins <joao.m.martins@...cle.com>

Declare various causes of emulation and use them as appropriate.

Signed-off-by: Joao Martins <joao.m.martins@...cle.com>
Signed-off-by: David Edmondson <david.edmondson@...cle.com>
---
 arch/x86/include/asm/kvm_host.h |  6 ++++++
 arch/x86/kvm/svm/avic.c         |  3 ++-
 arch/x86/kvm/svm/svm.c          | 26 +++++++++++++++-----------
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 79e9ca756742..e1284680cbdc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1535,6 +1535,12 @@ enum {
 	EMULREASON_IO_COMPLETE,
 	EMULREASON_UD,
 	EMULREASON_PF,
+	EMULREASON_SVM_NOASSIST,
+	EMULREASON_SVM_RSM,
+	EMULREASON_SVM_RDPMC,
+	EMULREASON_SVM_CR,
+	EMULREASON_SVM_DR,
+	EMULREASON_SVM_AVIC_UNACCEL,
 };
 
 int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type,
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 31a17fa6a37c..faa5d4db7ccc 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -558,7 +558,8 @@ int avic_unaccelerated_access_interception(struct vcpu_svm *svm)
 		ret = avic_unaccel_trap_write(svm);
 	} else {
 		/* Handling Fault */
-		ret = kvm_emulate_instruction(&svm->vcpu, 0, 0);
+		ret = kvm_emulate_instruction(&svm->vcpu, 0,
+					      EMULREASON_SVM_AVIC_UNACCEL);
 	}
 
 	return ret;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index bba3b72390a8..2646aa2eae22 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -344,7 +344,8 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	}
 
 	if (!svm->next_rip) {
-		if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP, 0))
+		if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP,
+					     EMULREASON_SKIP))
 			return 0;
 	} else {
 		kvm_rip_write(vcpu, svm->next_rip);
@@ -2077,7 +2078,8 @@ static int io_interception(struct vcpu_svm *svm)
 		if (sev_es_guest(vcpu->kvm))
 			return sev_es_string_io(svm, size, port, in);
 		else
-			return kvm_emulate_instruction(vcpu, 0, 0);
+			return kvm_emulate_instruction(vcpu, 0,
+						       EMULREASON_IO);
 	}
 
 	svm->next_rip = svm->vmcb->control.exit_info_2;
@@ -2263,7 +2265,8 @@ static int gp_interception(struct vcpu_svm *svm)
 		 */
 		if (!is_guest_mode(vcpu))
 			return kvm_emulate_instruction(vcpu,
-				EMULTYPE_VMWARE_GP | EMULTYPE_NO_DECODE, 0);
+				EMULTYPE_VMWARE_GP | EMULTYPE_NO_DECODE,
+				EMULREASON_GP);
 	} else
 		return emulate_svm_instr(vcpu, opcode);
 
@@ -2459,20 +2462,21 @@ static int invd_interception(struct vcpu_svm *svm)
 static int invlpg_interception(struct vcpu_svm *svm)
 {
 	if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
-		return kvm_emulate_instruction(&svm->vcpu, 0, 0);
+		return kvm_emulate_instruction(&svm->vcpu, 0, EMULREASON_SVM_NOASSIST);
 
 	kvm_mmu_invlpg(&svm->vcpu, svm->vmcb->control.exit_info_1);
 	return kvm_skip_emulated_instruction(&svm->vcpu);
 }
 
-static int emulate_on_interception(struct vcpu_svm *svm)
+static int emulate_on_interception(struct vcpu_svm *svm, int emulation_reason)
 {
-	return kvm_emulate_instruction(&svm->vcpu, 0, 0);
+	return kvm_emulate_instruction(&svm->vcpu, 0, emulation_reason);
 }
 
 static int rsm_interception(struct vcpu_svm *svm)
 {
-	return kvm_emulate_instruction_from_buffer(&svm->vcpu, rsm_ins_bytes, 2, 0);
+	return kvm_emulate_instruction_from_buffer(&svm->vcpu, rsm_ins_bytes, 2,
+						   EMULREASON_SVM_RSM);
 }
 
 static int rdpmc_interception(struct vcpu_svm *svm)
@@ -2480,7 +2484,7 @@ static int rdpmc_interception(struct vcpu_svm *svm)
 	int err;
 
 	if (!nrips)
-		return emulate_on_interception(svm);
+		return emulate_on_interception(svm, EMULREASON_SVM_RDPMC);
 
 	err = kvm_rdpmc(&svm->vcpu);
 	return kvm_complete_insn_gp(&svm->vcpu, err);
@@ -2516,10 +2520,10 @@ static int cr_interception(struct vcpu_svm *svm)
 	int err;
 
 	if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
-		return emulate_on_interception(svm);
+		return emulate_on_interception(svm, EMULREASON_SVM_NOASSIST);
 
 	if (unlikely((svm->vmcb->control.exit_info_1 & CR_VALID) == 0))
-		return emulate_on_interception(svm);
+		return emulate_on_interception(svm, EMULREASON_SVM_CR);
 
 	reg = svm->vmcb->control.exit_info_1 & SVM_EXITINFO_REG_MASK;
 	if (svm->vmcb->control.exit_code == SVM_EXIT_CR0_SEL_WRITE)
@@ -2635,7 +2639,7 @@ static int dr_interception(struct vcpu_svm *svm)
 	}
 
 	if (!boot_cpu_has(X86_FEATURE_DECODEASSISTS))
-		return emulate_on_interception(svm);
+		return emulate_on_interception(svm, EMULREASON_SVM_NOASSIST);
 
 	reg = svm->vmcb->control.exit_info_1 & SVM_EXITINFO_REG_MASK;
 	dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
-- 
2.30.2