KVM: PPC: Move xics_debugfs_init out of create

As we are about to hold the kvm->lock during the create operation on KVM
devices, we should move the call to xics_debugfs_init into its own
function, since holding a mutex over extended amounts of time might not
be a good idea.

Introduce an init operation on the kvm_device_ops struct which cannot
fail and call this, if configured, after the device has been created.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index a75ba38..f2def8e 100644 (file)
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -1341,8 +1341,6 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
                return ret;
        }
 
-       xics_debugfs_init(xics);
-
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
        if (cpu_has_feature(CPU_FTR_ARCH_206)) {
                /* Enable real mode support */
@@ -1354,9 +1352,17 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
        return 0;
 }
 
+static void kvmppc_xics_init(struct kvm_device *dev)
+{
+       struct kvmppc_xics *xics = (struct kvmppc_xics *)dev->private;
+
+       xics_debugfs_init(xics);
+}
+
 struct kvm_device_ops kvm_xics_ops = {
        .name = "kvm-xics",
        .create = kvmppc_xics_create,
+       .init = kvmppc_xics_init,
        .destroy = kvmppc_xics_free,
        .set_attr = xics_set_attr,
        .get_attr = xics_get_attr,

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 01e908a..d3c9b82 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1115,6 +1115,12 @@ struct kvm_device_ops {
        const char *name;
        int (*create)(struct kvm_device *dev, u32 type);
 
+       /*
+        * init is called after create if create is successful and is called
+        * outside of holding kvm->lock.
+        */
+       void (*init)(struct kvm_device *dev);
+
        /*
         * Destroy is responsible for freeing dev.
         *

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cc081cc..ae64245 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2838,6 +2838,9 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
                return ret;
        }
 
+       if (ops->init)
+               ops->init(dev);
+
        ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
        if (ret < 0) {
                ops->destroy(dev);