linux-kernel - [PATCH 1/2] KVM: x86: Invert APICv/AVIC enablement check

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Message-Id: <20210513113710.1740398-2-vkuznets@redhat.com>
Date:   Thu, 13 May 2021 13:37:09 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Kechen Lu <kechenl@...dia.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] KVM: x86: Invert APICv/AVIC enablement check

Currently, APICv/AVIC enablement is global ('enable_apicv' module parameter
for Intel, 'avic' module parameter for AMD) but there's no way to check
it from vendor-neutral code. Add 'apicv_supported()' to kvm_x86_ops and
invert kvm_apicv_init() (which now doesn't need to be called from arch-
specific code).

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/svm/svm.c          | 7 ++++++-
 arch/x86/kvm/vmx/vmx.c          | 7 ++++++-
 arch/x86/kvm/x86.c              | 6 +++---
 4 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 55efbacfc244..ffafdb7b24cb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1205,6 +1205,7 @@ struct kvm_x86_ops {
 	void (*hardware_unsetup)(void);
 	bool (*cpu_has_accelerated_tpr)(void);
 	bool (*has_emulated_msr)(struct kvm *kvm, u32 index);
+	bool (*apicv_supported)(void);
 	void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);
 
 	unsigned int vm_size;
@@ -1661,7 +1662,6 @@ gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,
 				struct x86_exception *exception);
 
 bool kvm_apicv_activated(struct kvm *kvm);
-void kvm_apicv_init(struct kvm *kvm, bool enable);
 void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu);
 void kvm_request_apicv_update(struct kvm *kvm, bool activate,
 			      unsigned long bit);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4dd9b7856e5b..360b3000c5a8 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4470,16 +4470,21 @@ static int svm_vm_init(struct kvm *kvm)
 			return ret;
 	}
 
-	kvm_apicv_init(kvm, avic);
 	return 0;
 }
 
+static bool svm_avic_supported(void)
+{
+	return avic;
+}
+
 static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.hardware_unsetup = svm_hardware_teardown,
 	.hardware_enable = svm_hardware_enable,
 	.hardware_disable = svm_hardware_disable,
 	.cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
 	.has_emulated_msr = svm_has_emulated_msr,
+	.apicv_supported = svm_avic_supported,
 
 	.vcpu_create = svm_create_vcpu,
 	.vcpu_free = svm_free_vcpu,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f2fd447eed45..3b0f4f9c21b3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7034,7 +7034,6 @@ static int vmx_vm_init(struct kvm *kvm)
 			break;
 		}
 	}
-	kvm_apicv_init(kvm, enable_apicv);
 	return 0;
 }
 
@@ -7645,6 +7644,11 @@ static bool vmx_check_apicv_inhibit_reasons(ulong bit)
 	return supported & BIT(bit);
 }
 
+static bool vmx_apicv_supported(void)
+{
+	return enable_apicv;
+}
+
 static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.hardware_unsetup = hardware_unsetup,
 
@@ -7652,6 +7656,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.hardware_disable = hardware_disable,
 	.cpu_has_accelerated_tpr = report_flexpriority,
 	.has_emulated_msr = vmx_has_emulated_msr,
+	.apicv_supported = vmx_apicv_supported,
 
 	.vm_size = sizeof(struct kvm_vmx),
 	.vm_init = vmx_vm_init,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5bd550eaf683..fe7248e11e13 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8342,16 +8342,15 @@ bool kvm_apicv_activated(struct kvm *kvm)
 }
 EXPORT_SYMBOL_GPL(kvm_apicv_activated);
 
-void kvm_apicv_init(struct kvm *kvm, bool enable)
+static void kvm_apicv_init(struct kvm *kvm)
 {
-	if (enable)
+	if (kvm_x86_ops.apicv_supported())
 		clear_bit(APICV_INHIBIT_REASON_DISABLE,
 			  &kvm->arch.apicv_inhibit_reasons);
 	else
 		set_bit(APICV_INHIBIT_REASON_DISABLE,
 			&kvm->arch.apicv_inhibit_reasons);
 }
-EXPORT_SYMBOL_GPL(kvm_apicv_init);
 
 static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id)
 {
@@ -10727,6 +10726,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn);
 	INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn);
 
+	kvm_apicv_init(kvm);
 	kvm_hv_init_vm(kvm);
 	kvm_page_track_init(kvm);
 	kvm_mmu_init_vm(kvm);
-- 
2.31.1