linux-kernel - [RESEND v13 01/10] KVM: x86: Move common set/get handler of MSR_IA32

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Date:   Fri,  8 Jan 2021 09:36:55 +0800
From:   Like Xu <like.xu@...ux.intel.com>
To:     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>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>, ak@...ux.intel.com,
        wei.w.wang@...el.com, kan.liang@...el.com, x86@...nel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RESEND v13 01/10] KVM: x86: Move common set/get handler of MSR_IA32_DEBUGCTLMSR to VMX

SVM already has specific handlers of MSR_IA32_DEBUGCTLMSR in the
svm_get/set_msr, so the x86 common part can be safely moved to VMX.

Add vmx_supported_debugctl() to refactor the throwing logic of #GP.

Signed-off-by: Like Xu <like.xu@...ux.intel.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/kvm/vmx/capabilities.h |  5 +++++
 arch/x86/kvm/vmx/vmx.c          | 19 ++++++++++++++++---
 arch/x86/kvm/x86.c              | 13 -------------
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 3a1861403d73..a58cf3655351 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -378,4 +378,9 @@ static inline u64 vmx_get_perf_capabilities(void)
 	return PMU_CAP_FW_WRITES;
 }
 
+static inline u64 vmx_supported_debugctl(void)
+{
+	return DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF;
+}
+
 #endif /* __KVM_X86_VMX_CAPS_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2af05d3b0590..23b46327527e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1924,6 +1924,9 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		    !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
 			return 1;
 		goto find_uret_msr;
+	case MSR_IA32_DEBUGCTLMSR:
+		msr_info->data = 0;
+		break;
 	default:
 	find_uret_msr:
 		msr = vmx_find_uret_msr(vmx, msr_info->index);
@@ -2002,9 +2005,19 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 						VM_EXIT_SAVE_DEBUG_CONTROLS)
 			get_vmcs12(vcpu)->guest_ia32_debugctl = data;
 
-		ret = kvm_set_msr_common(vcpu, msr_info);
-		break;
-
+		if (!data) {
+			/* We support the non-activated case already */
+			return 0;
+		} else if (data & ~vmx_supported_debugctl()) {
+			/*
+			 * Values other than LBR and BTF are vendor-specific,
+			 * thus reserved and should throw a #GP.
+			 */
+			return 1;
+		}
+		vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
+			    __func__, data);
+		return 0;
 	case MSR_IA32_BNDCFGS:
 		if (!kvm_mpx_supported() ||
 		    (!msr_info->host_initiated &&
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0287840b93e0..c765fd72a66c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3063,18 +3063,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		}
 		break;
-	case MSR_IA32_DEBUGCTLMSR:
-		if (!data) {
-			/* We support the non-activated case already */
-			break;
-		} else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
-			/* Values other than LBR and BTF are vendor-specific,
-			   thus reserved and should throw a #GP */
-			return 1;
-		} else if (report_ignored_msrs)
-			vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
-				    __func__, data);
-		break;
 	case 0x200 ... 0x2ff:
 		return kvm_mtrr_set_msr(vcpu, msr, data);
 	case MSR_IA32_APICBASE:
@@ -3347,7 +3335,6 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	switch (msr_info->index) {
 	case MSR_IA32_PLATFORM_ID:
 	case MSR_IA32_EBL_CR_POWERON:
-	case MSR_IA32_DEBUGCTLMSR:
 	case MSR_IA32_LASTBRANCHFROMIP:
 	case MSR_IA32_LASTBRANCHTOIP:
 	case MSR_IA32_LASTINTFROMIP:
-- 
2.29.2