kvm: Allow build-time configuration of KVM device assignment

We hope to at some point deprecate KVM legacy device assignment in
favor of VFIO-based assignment.  Towards that end, allow legacy
device assignment to be deconfigured.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

2 files changed, 8 insertions, 26 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 309774715897..996661eb8e99 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -667,7 +667,6 @@ static inline wait_queue_head_t *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
 
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
 void kvm_arch_destroy_vm(struct kvm *kvm);
-void kvm_free_all_assigned_devices(struct kvm *kvm);
 void kvm_arch_sync_events(struct kvm *kvm);
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu);
@@ -736,7 +735,7 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
 /* For vcpu->arch.iommu_flags */
 #define KVM_IOMMU_CACHE_COHERENCY       0x1
 
-#ifdef CONFIG_IOMMU_API
+#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot);
 void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot);
 int kvm_iommu_map_guest(struct kvm *kvm);
@@ -745,7 +744,7 @@ int kvm_assign_device(struct kvm *kvm,
                       struct kvm_assigned_dev_kernel *assigned_dev);
 int kvm_deassign_device(struct kvm *kvm,
                         struct kvm_assigned_dev_kernel *assigned_dev);
-#else /* CONFIG_IOMMU_API */
+#else
 static inline int kvm_iommu_map_pages(struct kvm *kvm,
                                       struct kvm_memory_slot *slot)
 {
@@ -757,28 +756,11 @@ static inline void kvm_iommu_unmap_pages(struct kvm *kvm,
 {
 }
 
-static inline int kvm_iommu_map_guest(struct kvm *kvm)
-{
-        return -ENODEV;
-}
-
 static inline int kvm_iommu_unmap_guest(struct kvm *kvm)
 {
         return 0;
 }
-
-static inline int kvm_assign_device(struct kvm *kvm,
-                struct kvm_assigned_dev_kernel *assigned_dev)
-{
-        return 0;
-}
-
-static inline int kvm_deassign_device(struct kvm *kvm,
-                struct kvm_assigned_dev_kernel *assigned_dev)
-{
-        return 0;
-}
-#endif /* CONFIG_IOMMU_API */
+#endif
 
 static inline void __guest_enter(void)
 {
@@ -1032,11 +1014,13 @@ static inline bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) { return true; }
 
 #endif
 
-#ifdef __KVM_HAVE_DEVICE_ASSIGNMENT
+#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
 
 long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
                                   unsigned long arg);
 
+void kvm_free_all_assigned_devices(struct kvm *kvm);
+
 #else
 
 static inline long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
@@ -1045,6 +1029,8 @@ static inline long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
         return -ENOTTY;
 }
 
+static inline void kvm_free_all_assigned_devices(struct kvm *kvm) {}
+
 #endif
 
 static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d4005192ad6e..965e5b52dee0 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -561,9 +561,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_MP_STATE 14
 #define KVM_CAP_COALESCED_MMIO 15
 #define KVM_CAP_SYNC_MMU 16  /* Changes to host mmap are reflected in guest */
-#ifdef __KVM_HAVE_DEVICE_ASSIGNMENT
 #define KVM_CAP_DEVICE_ASSIGNMENT 17
-#endif
 #define KVM_CAP_IOMMU 18
 #ifdef __KVM_HAVE_MSI
 #define KVM_CAP_DEVICE_MSI 20
@@ -581,9 +579,7 @@ struct kvm_ppc_smmu_info {
 #endif
 #define KVM_CAP_IRQ_ROUTING 25
 #define KVM_CAP_IRQ_INJECT_STATUS 26
-#ifdef __KVM_HAVE_DEVICE_ASSIGNMENT
 #define KVM_CAP_DEVICE_DEASSIGNMENT 27
-#endif
 #ifdef __KVM_HAVE_MSIX
 #define KVM_CAP_DEVICE_MSIX 28
 #endif