kvm_ioctl_create_device currently has knowledge of all the device types
and their associated ops. This is fairly inflexible when adding support
for new in-kernel device emulations, so move what we currently have out
into a table, which can support dynamic registration of ops by new
drivers for virtual hardware.
I didn't try to port all current drivers over, as it's not always clear
which initialisation hook the ops should be registered from.
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
Hi guys,
I've just started writing a virtual IOMMU for the ARM SMMU and figured a
registration mechanism for kvm_device_ops would be a nice cleanup for
that.
Will
include/linux/kvm_host.h | 1 +
include/uapi/linux/kvm.h | 1 +
virt/kvm/kvm_main.c | 65 ++++++++++++++++++++++++++++--------------------
3 files changed, 40 insertions(+), 27 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ec4e3bd83d47..b75faaf0d76d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1083,6 +1083,7 @@ struct kvm_device_ops {
void kvm_device_get(struct kvm_device *dev);
void kvm_device_put(struct kvm_device *dev);
struct kvm_device *kvm_device_from_filp(struct file *filp);
+int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type);
extern struct kvm_device_ops kvm_mpic_ops;
extern struct kvm_device_ops kvm_xics_ops;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index e11d8f170a62..3b368166286f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -949,6 +949,7 @@ struct kvm_device_attr {
#define KVM_DEV_VFIO_GROUP_DEL 2
#define KVM_DEV_TYPE_ARM_VGIC_V2 5
#define KVM_DEV_TYPE_FLIC 6
+#define KVM_DEV_TYPE_MAX 7
/*
* ioctls for VM fds
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4b6c01b477f9..a0c6cc31a1f6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2257,44 +2257,55 @@ struct kvm_device *kvm_device_from_filp(struct file *filp)
return filp->private_data;
}
-static int kvm_ioctl_create_device(struct kvm *kvm,
- struct kvm_create_device *cd)
-{
- struct kvm_device_ops *ops = NULL;
- struct kvm_device *dev;
- bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
- int ret;
-
- switch (cd->type) {
+static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
#ifdef CONFIG_KVM_MPIC
- case KVM_DEV_TYPE_FSL_MPIC_20:
- case KVM_DEV_TYPE_FSL_MPIC_42:
- ops = &kvm_mpic_ops;
- break;
+ [KVM_DEV_TYPE_FSL_MPIC_20] = &kvm_mpic_ops,
+ [KVM_DEV_TYPE_FSL_MPIC_42] = &kvm_mpic_ops,
#endif
+
#ifdef CONFIG_KVM_XICS
- case KVM_DEV_TYPE_XICS:
- ops = &kvm_xics_ops;
- break;
+ [KVM_DEV_TYPE_XICS] = &kvm_xics_ops,
#endif
+
#ifdef CONFIG_KVM_VFIO
- case KVM_DEV_TYPE_VFIO:
- ops = &kvm_vfio_ops;
- break;
+ [KVM_DEV_TYPE_VFIO] = &kvm_vfio_ops,
#endif
+
#ifdef CONFIG_KVM_ARM_VGIC
- case KVM_DEV_TYPE_ARM_VGIC_V2:
- ops = &kvm_arm_vgic_v2_ops;
- break;
+ [KVM_DEV_TYPE_ARM_VGIC_V2] = &kvm_arm_vgic_v2_ops,
#endif
+
#ifdef CONFIG_S390
- case KVM_DEV_TYPE_FLIC:
- ops = &kvm_flic_ops;
- break;
+ [KVM_DEV_TYPE_FLIC] = &kvm_flic_ops;
#endif
- default:
+};
+
+int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
+{
+ if (type >= KVM_DEV_TYPE_MAX)
+ return -ENOSPC;
+
+ if (kvm_device_ops_table[type] != NULL)
+ return -EEXIST;
+
+ kvm_device_ops_table[type] = ops;
+ return 0;
+}
+
+static int kvm_ioctl_create_device(struct kvm *kvm,
+ struct kvm_create_device *cd)
+{
+ struct kvm_device_ops *ops = NULL;
+ struct kvm_device *dev;
+ bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
+ int ret;
+
+ if (cd->type >= KVM_DEV_TYPE_MAX)
+ return -ENODEV;
+
+ ops = kvm_device_ops_table[cd->type];
+ if (ops == NULL)
return -ENODEV;
- }
if (test)
return 0;
--
2.0.0
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