[PATCH RFC v2 05/12] s390x/css: realize css_create_sch

Dong Jia Shi
2017-01-12T07:25:06Z

The S390 virtual css support already has a mechanism to create a
virtual subchannel and provide it to the guest. However, to
pass-through subchannels to a guest, we need to introduce a new
mechanism to create the subchannel according to the real device
information. Thus we realize a new css_create_sch function to
allocate and initialize the subchannel according to the real
device information.

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
hw/s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++
include/hw/s390x/css.h | 15 +++++++++++++++
2 files changed, 54 insertions(+)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 8703bc3..67fe468 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1486,6 +1486,19 @@ bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno)
channel_subsys.css[cssid]->sch_set[ssid]->devnos_used);
}

+bool css_schid_used(uint8_t cssid, uint8_t ssid, uint16_t schid)
+{
+ if (!channel_subsys.css[cssid]) {
+ return false;
+ }
+ if (!channel_subsys.css[cssid]->sch_set[ssid]) {
+ return false;
+ }
+
+ return !!test_bit(schid,
+ channel_subsys.css[cssid]->sch_set[ssid]->schids_used);
+}
+
void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
uint16_t devno, SubchDev *sch)
{
@@ -1911,6 +1924,32 @@ SubchDev *css_create_virtual_sch(CssDevId bus_id, Error **errp)
return sch;
}

+SubchDev *css_create_sch(CssDevId bus_id, Error **errp)
+{
+ uint32_t devno;
+ SubchDev *sch;
+
+ if (css_schid_used(bus_id.cssid, bus_id.ssid, bus_id.devid)) {
+ error_setg(errp, "Subchannel %x.%x.%04x already exists",
+ bus_id.cssid, bus_id.ssid, bus_id.devid);
+ return NULL;
+ }
+
+ devno = css_find_free_devno(bus_id.cssid, bus_id.ssid, bus_id.devid);
+ if (devno > MAX_DEVNO) {
+ error_setg(errp, "No free devno found");
+ return NULL;
+ }
+
+ sch = g_malloc0(sizeof(*sch));
+ sch->cssid = bus_id.cssid;
+ sch->ssid = bus_id.ssid;
+ sch->devno = devno;
+ sch->schid = bus_id.devid;
+ css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, sch);
+ return sch;
+}
+
static int css_sch_get_chpids(SubchDev *sch, CssDevId *dev_id)
{
char *fid_path;
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index 648ea2f..c92f624 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -128,6 +128,7 @@ void subch_device_save(SubchDev *s, QEMUFile *f);
int subch_device_load(SubchDev *s, QEMUFile *f);
int css_create_css_image(uint8_t cssid, bool default_image);
bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno);
+bool css_schid_used(uint8_t cssid, uint8_t ssid, uint16_t schid);
void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
uint16_t devno, SubchDev *sch);
void css_sch_build_virtual_schib(SubchDev *sch, uint8_t chpid, uint8_t type);
@@ -189,4 +190,18 @@ bool css_present(uint8_t cssid);
* is responsible for unregistering and freeing it.
*/
SubchDev *css_create_virtual_sch(CssDevId bus_id, Error **errp);
+
+/**
+ * Create a subchannel for the given bus id.
+ *
+ * If @p bus_id is valid, verify that it is not already in use, and find
+ * a free devno for it.
+ * Allocate a subchannel structure, initialise it with the bus id,
+ * subchannel id and device number, register it with the CSS and return
+ * it. Otherwise return NULL.
+ *
+ * The caller becomes owner of the returned subchannel structure and
+ * is responsible for unregistering and freeing it.
+ */
+SubchDev *css_create_sch(CssDevId bus_id, Error **errp);
#endif
--
2.8.4