s390x/css: factor out some generic code from virtio_ccw_device_realize()
A lot of what virtio_ccw_device_realize() does isn't specific to
virtio; it would apply to emulated CCW as well. Factor it out to make
it easier to implement emulated CCW devices later on.
Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 7666881..54991f5 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1340,6 +1340,116 @@
return channel_subsys.css[real_cssid]->sch_set[ssid]->sch[schid];
}
+/**
+ * Return free device number in subchannel set.
+ *
+ * Return index of the first free device number in the subchannel set
+ * identified by @p cssid and @p ssid, beginning the search at @p
+ * start and wrapping around at MAX_DEVNO. Return a value exceeding
+ * MAX_SCHID if there are no free device numbers in the subchannel
+ * set.
+ */
+static uint32_t css_find_free_devno(uint8_t cssid, uint8_t ssid,
+ uint16_t start)
+{
+ uint32_t round;
+
+ for (round = 0; round <= MAX_DEVNO; round++) {
+ uint16_t devno = (start + round) % MAX_DEVNO;
+
+ if (!css_devno_used(cssid, ssid, devno)) {
+ return devno;
+ }
+ }
+ return MAX_DEVNO + 1;
+}
+
+/**
+ * Return first free subchannel (id) in subchannel set.
+ *
+ * Return index of the first free subchannel in the subchannel set
+ * identified by @p cssid and @p ssid, if there is any. Return a value
+ * exceeding MAX_SCHID if there are no free subchannels in the
+ * subchannel set.
+ */
+static uint32_t css_find_free_subch(uint8_t cssid, uint8_t ssid)
+{
+ uint32_t schid;
+
+ for (schid = 0; schid <= MAX_SCHID; schid++) {
+ if (!css_find_subch(1, cssid, ssid, schid)) {
+ return schid;
+ }
+ }
+ return MAX_SCHID + 1;
+}
+
+/**
+ * Return first free subchannel (id) in subchannel set for a device number
+ *
+ * Verify the device number @p devno is not used yet in the subchannel
+ * set identified by @p cssid and @p ssid. Set @p schid to the index
+ * of the first free subchannel in the subchannel set, if there is
+ * any. Return true if everything succeeded and false otherwise.
+ */
+static bool css_find_free_subch_for_devno(uint8_t cssid, uint8_t ssid,
+ uint16_t devno, uint16_t *schid,
+ Error **errp)
+{
+ uint32_t free_schid;
+
+ assert(schid);
+ if (css_devno_used(cssid, ssid, devno)) {
+ error_setg(errp, "Device %x.%x.%04x already exists",
+ cssid, ssid, devno);
+ return false;
+ }
+ free_schid = css_find_free_subch(cssid, ssid);
+ if (free_schid > MAX_SCHID) {
+ error_setg(errp, "No free subchannel found for %x.%x.%04x",
+ cssid, ssid, devno);
+ return false;
+ }
+ *schid = free_schid;
+ return true;
+}
+
+/**
+ * Return first free subchannel (id) and device number
+ *
+ * Locate the first free subchannel and first free device number in
+ * any of the subchannel sets of the channel subsystem identified by
+ * @p cssid. Return false if no free subchannel / device number could
+ * be found. Otherwise set @p ssid, @p devno and @p schid to identify
+ * the available subchannel and device number and return true.
+ *
+ * May modify @p ssid, @p devno and / or @p schid even if no free
+ * subchannel / device number could be found.
+ */
+static bool css_find_free_subch_and_devno(uint8_t cssid, uint8_t *ssid,
+ uint16_t *devno, uint16_t *schid,
+ Error **errp)
+{
+ uint32_t free_schid, free_devno;
+
+ assert(ssid && devno && schid);
+ for (*ssid = 0; *ssid <= MAX_SSID; (*ssid)++) {
+ free_schid = css_find_free_subch(cssid, *ssid);
+ if (free_schid > MAX_SCHID) {
+ continue;
+ }
+ free_devno = css_find_free_devno(cssid, *ssid, free_schid);
+ if (free_devno > MAX_DEVNO) {
+ continue;
+ }
+ *schid = free_schid;
+ *devno = free_devno;
+ return true;
+ }
+ error_setg(errp, "Virtual channel subsystem is full!");
+ return false;
+}
+
bool css_subch_visible(SubchDev *sch)
{
if (sch->ssid > channel_subsys.max_ssid) {
@@ -1762,3 +1872,36 @@
.get = get_css_devid,
.set = set_css_devid,
};
+
+SubchDev *css_create_virtual_sch(CssDevId bus_id, Error **errp)
+{
+ uint16_t schid = 0;
+ SubchDev *sch;
+
+ if (bus_id.valid) {
+ /* Enforce use of virtual cssid. */
+ if (bus_id.cssid != VIRTUAL_CSSID) {
+ error_setg(errp, "cssid %hhx not valid for virtual devices",
+ bus_id.cssid);
+ return NULL;
+ }
+ if (!css_find_free_subch_for_devno(bus_id.cssid, bus_id.ssid,
+ bus_id.devid, &schid, errp)) {
+ return NULL;
+ }
+ } else {
+ bus_id.cssid = VIRTUAL_CSSID;
+ if (!css_find_free_subch_and_devno(bus_id.cssid, &bus_id.ssid,
+ &bus_id.devid, &schid, errp)) {
+ return NULL;
+ }
+ }
+
+ sch = g_malloc0(sizeof(*sch));
+ sch->cssid = bus_id.cssid;
+ sch->ssid = bus_id.ssid;
+ sch->devno = bus_id.devid;
+ sch->schid = schid;
+ css_subch_assign(sch->cssid, sch->ssid, schid, sch->devno, sch);
+ return sch;
+}
