aboutsummaryrefslogtreecommitdiff
path: root/drivers/xen/xenbus
diff options
context:
space:
mode:
authorBastian Blank <waldi@debian.org>2011-12-10 19:29:48 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-12-16 13:29:41 -0500
commite9f0fec3f5d406c500861da779d16a779a110055 (patch)
tree54746773f093c060f1112ad1d8067d37010b92a3 /drivers/xen/xenbus
parent2fb3683e7b164ee2b324039f7c9d90fe5b1a259b (diff)
downloadvexpress-lsk-e9f0fec3f5d406c500861da779d16a779a110055.tar.gz
xen: Add xenbus_backend device
Access for xenstored to the event channel and pre-allocated ring is managed via xenfs. This adds its own character device featuring mmap for the ring and an ioctl for the event channel. Signed-off-by: Bastian Blank <waldi@debian.org> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen/xenbus')
-rw-r--r--drivers/xen/xenbus/Makefile1
-rw-r--r--drivers/xen/xenbus/xenbus_dev_backend.c89
2 files changed, 90 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/Makefile b/drivers/xen/xenbus/Makefile
index a2ea363b9f3..31e2e9050c7 100644
--- a/drivers/xen/xenbus/Makefile
+++ b/drivers/xen/xenbus/Makefile
@@ -10,4 +10,5 @@ xenbus-objs += xenbus_probe.o
xenbus-be-objs-$(CONFIG_XEN_BACKEND) += xenbus_probe_backend.o
xenbus-objs += $(xenbus-be-objs-y)
+obj-$(CONFIG_XEN_BACKEND) += xenbus_dev_backend.o
obj-$(CONFIG_XEN_XENBUS_FRONTEND) += xenbus_probe_frontend.o
diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c
new file mode 100644
index 00000000000..a2092bd9769
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_dev_backend.c
@@ -0,0 +1,89 @@
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/capability.h>
+
+#include <xen/page.h>
+#include <xen/xenbus_dev.h>
+
+#include "xenbus_comms.h"
+
+MODULE_LICENSE("GPL");
+
+static int xenbus_backend_open(struct inode *inode, struct file *filp)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return nonseekable_open(inode, filp);
+}
+
+static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ switch (cmd) {
+ case IOCTL_XENBUS_BACKEND_EVTCHN:
+ if (xen_store_evtchn > 0)
+ return xen_store_evtchn;
+ return -ENODEV;
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ size_t size = vma->vm_end - vma->vm_start;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
+ return -EINVAL;
+
+ if (remap_pfn_range(vma, vma->vm_start,
+ virt_to_pfn(xen_store_interface),
+ size, vma->vm_page_prot))
+ return -EAGAIN;
+
+ return 0;
+}
+
+const struct file_operations xenbus_backend_fops = {
+ .open = xenbus_backend_open,
+ .mmap = xenbus_backend_mmap,
+ .unlocked_ioctl = xenbus_backend_ioctl,
+};
+
+static struct miscdevice xenbus_backend_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "xen/xenbus_backend",
+ .fops = &xenbus_backend_fops,
+};
+
+static int __init xenbus_backend_init(void)
+{
+ int err;
+
+ if (!xen_initial_domain())
+ return -ENODEV;
+
+ err = misc_register(&xenbus_backend_dev);
+ if (err)
+ printk(KERN_ERR "Could not register xenbus backend device\n");
+ return err;
+}
+
+static void __exit xenbus_backend_exit(void)
+{
+ misc_deregister(&xenbus_backend_dev);
+}
+
+module_init(xenbus_backend_init);
+module_exit(xenbus_backend_exit);