s390x/css: introduce property type for device ids

Let's introduce a CssDevId to handle device ids of the xx.x.xxxx
type used for channel devices. This has some benefits:

- We can use them in virtio-ccw and split the validity checks for
  a channel device id in general from the constraint checking
  within the virtio-ccw scope.
- We can reuse the device id type for future non-virtio channel
  devices.

While we're at it, improve the validity checks and disallow e.g.
trailing characters.

Suggested-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Acked-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index 98b2e2c..38f4d77 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -151,5 +151,22 @@ int css_do_rsch(SubchDev *sch);
 int css_do_rchp(uint8_t cssid, uint8_t chpid);
 bool css_present(uint8_t cssid);
 #endif
+/*
+ * Identify a device within the channel subsystem.
+ * Note that this can be used to identify either the subchannel or
+ * the attached I/O device, as there's always one I/O device per
+ * subchannel.
+ */
+typedef struct CssDevId {
+    uint8_t cssid;
+    uint8_t ssid;
+    uint16_t devid;
+    bool valid;
+} CssDevId;
+
+extern PropertyInfo css_devid_propinfo;
+
+#define DEFINE_PROP_CSS_DEV_ID(_n, _s, _f) \
+    DEFINE_PROP(_n, _s, _f, css_devid_propinfo, CssDevId)
 
 #endif