linux-kernel - [PATCH v3 1/6] KVM: x86: return 1 unconditionally for availability of KVM_CAP

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Date:   Thu, 17 Feb 2022 13:08:26 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH v3 1/6] KVM: x86: return 1 unconditionally for availability of KVM_CAP_VAPIC

The two ioctl used to implement userspace-accelerated TPR,
KVM_TPR_ACCESS_REPORTING and KVM_SET_VAPIC_ADDR, are available
even if hardware-accelerated TPR can be used.  So there is
no reason not to report KVM_CAP_VAPIC.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/kvm-x86-ops.h | 1 -
 arch/x86/include/asm/kvm_host.h    | 1 -
 arch/x86/kvm/svm/svm.c             | 6 ------
 arch/x86/kvm/vmx/vmx.c             | 6 ------
 arch/x86/kvm/x86.c                 | 4 +---
 5 files changed, 1 insertion(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 9e37dc3d8863..695ed7feef7e 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -15,7 +15,6 @@ BUILD_BUG_ON(1)
 KVM_X86_OP_NULL(hardware_enable)
 KVM_X86_OP_NULL(hardware_disable)
 KVM_X86_OP_NULL(hardware_unsetup)
-KVM_X86_OP_NULL(cpu_has_accelerated_tpr)
 KVM_X86_OP(has_emulated_msr)
 KVM_X86_OP(vcpu_after_set_cpuid)
 KVM_X86_OP(vm_init)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 10815b672a26..e0d2cdfe54ab 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1318,7 +1318,6 @@ struct kvm_x86_ops {
 	int (*hardware_enable)(void);
 	void (*hardware_disable)(void);
 	void (*hardware_unsetup)(void);
-	bool (*cpu_has_accelerated_tpr)(void);
 	bool (*has_emulated_msr)(struct kvm *kvm, u32 index);
 	void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4243bb355db0..abced3fe2013 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3912,11 +3912,6 @@ static int __init svm_check_processor_compat(void)
 	return 0;
 }
 
-static bool svm_cpu_has_accelerated_tpr(void)
-{
-	return false;
-}
-
 /*
  * The kvm parameter can be NULL (module initialization, or invocation before
  * VM creation). Be sure to check the kvm parameter before using it.
@@ -4529,7 +4524,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.hardware_unsetup = svm_hardware_unsetup,
 	.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,
 
 	.vcpu_create = svm_vcpu_create,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 70e7f00362bc..d8547144d3b7 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -541,11 +541,6 @@ static inline bool cpu_need_virtualize_apic_accesses(struct kvm_vcpu *vcpu)
 	return flexpriority_enabled && lapic_in_kernel(vcpu);
 }
 
-static inline bool vmx_cpu_has_accelerated_tpr(void)
-{
-	return flexpriority_enabled;
-}
-
 static int possible_passthrough_msr_slot(u32 msr)
 {
 	u32 i;
@@ -7714,7 +7709,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 
 	.hardware_enable = vmx_hardware_enable,
 	.hardware_disable = vmx_hardware_disable,
-	.cpu_has_accelerated_tpr = vmx_cpu_has_accelerated_tpr,
 	.has_emulated_msr = vmx_has_emulated_msr,
 
 	.vm_size = sizeof(struct kvm_vmx),
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index eaa3b5b89c5e..746f72ae2c95 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4234,6 +4234,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_EXIT_ON_EMULATION_FAILURE:
 	case KVM_CAP_VCPU_ATTRIBUTES:
 	case KVM_CAP_SYS_ATTRIBUTES:
+	case KVM_CAP_VAPIC:
 		r = 1;
 		break;
 	case KVM_CAP_EXIT_HYPERCALL:
@@ -4274,9 +4275,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		 */
 		r = static_call(kvm_x86_has_emulated_msr)(kvm, MSR_IA32_SMBASE);
 		break;
-	case KVM_CAP_VAPIC:
-		r = !static_call(kvm_x86_cpu_has_accelerated_tpr)();
-		break;
 	case KVM_CAP_NR_VCPUS:
 		r = min_t(unsigned int, num_online_cpus(), KVM_MAX_VCPUS);
 		break;
-- 
2.31.1