While we can easily register and unregister KVM devices, there is
currently no easy way of checking whether a device has been
registered.
Introduce kvm_check_device() for that purpose and use it in two
existing functions. Also change the return code for an invalid
type number from ENOSPC to EINVAL.
This function will be later used by another patch set to check
whether a KVM_CREATE_IRQCHIP ioctl is valid.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
Hi,
can people comment whether there is an easier way to detect KVM
device registration _outside_ of virt/kvm/kvm_main.c? Using the
KVM_CREATE_DEVICE_TEST flag sounds like a fit, but
kvm_ioctl_create_device() isn't exported.
Also is my return code semantics too exerted?
Cheers,
Andre.
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 33 +++++++++++++++++++++------------
2 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 83d770e..78e94ef 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1038,6 +1038,7 @@ 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);
+int kvm_check_device(u32 type);
void kvm_unregister_device_ops(u32 type);
extern struct kvm_device_ops kvm_mpic_ops;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1cc6e2e..42604a9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2341,13 +2341,24 @@ static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
#endif
};
-int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
+int kvm_check_device(u32 type)
{
if (type >= ARRAY_SIZE(kvm_device_ops_table))
- return -ENOSPC;
+ return -EINVAL;
- if (kvm_device_ops_table[type] != NULL)
- return -EEXIST;
+ if (kvm_device_ops_table[type] == NULL)
+ return -ENODEV;
+
+ return -EEXIST;
+}
+
+int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
+{
+ int ret;
+
+ ret = kvm_check_device(type);
+ if (ret != -ENODEV)
+ return ret;
kvm_device_ops_table[type] = ops;
return 0;
@@ -2364,19 +2375,17 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
{
struct kvm_device_ops *ops = NULL;
struct kvm_device *dev;
- bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
int ret;
- if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
- return -ENODEV;
-
- ops = kvm_device_ops_table[cd->type];
- if (ops == NULL)
- return -ENODEV;
+ ret = kvm_check_device(cd->type);
+ if (ret != -EEXIST)
+ return ret;
- if (test)
+ if (cd->flags & KVM_CREATE_DEVICE_TEST)
return 0;
+ ops = kvm_device_ops_table[cd->type];
+
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
--
1.7.9.5
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