[PATCH v7 05/13] s390x/css: realize css_create_sch

Dong Jia Shi
2017-05-05T02:03:44Z

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 reconstruct css_create_virtual_sch to a new
css_create_sch function to handl all these cases and do allocation
and initialization of the subchannel according to the device type
and machine configuration.

Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
---
hw/s390x/css-bridge.c | 2 ++
hw/s390x/css.c | 45 ++++++++++++++++++++++++++++++++++++-------
hw/s390x/s390-virtio-ccw.c | 12 +++++++++---
hw/s390x/virtio-ccw.c | 6 +++++-
include/hw/s390x/css-bridge.h | 1 +
include/hw/s390x/css.h | 25 ++++++++++++++++--------
6 files changed, 72 insertions(+), 19 deletions(-)

diff --git a/hw/s390x/css-bridge.c b/hw/s390x/css-bridge.c
index b54ac01..823747f 100644
--- a/hw/s390x/css-bridge.c
+++ b/hw/s390x/css-bridge.c
@@ -17,6 +17,7 @@
#include "hw/s390x/css.h"
#include "ccw-device.h"
#include "hw/s390x/css-bridge.h"
+#include "cpu.h"

/*
* Invoke device-specific unplug handler, disable the subchannel
@@ -103,6 +104,7 @@ VirtualCssBus *virtual_css_bus_init(void)
/* Create bus on bridge device */
bus = qbus_create(TYPE_VIRTUAL_CSS_BUS, dev, "virtual-css");
cbus = VIRTUAL_CSS_BUS(bus);
+ cbus->squash_mcss = s390_get_squash_mcss();

/* Enable hotplugging */
qbus_set_hotplug_handler(bus, dev, &error_abort);
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 748e2ad..1052eea 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1924,28 +1924,59 @@ PropertyInfo css_devid_ro_propinfo = {
.get = get_css_devid,
};

-SubchDev *css_create_virtual_sch(CssDevId bus_id, Error **errp)
+SubchDev *css_create_sch(CssDevId bus_id, bool is_virtio, bool squash_mcss,
+ 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);
+ if (is_virtio != (bus_id.cssid == VIRTUAL_CSSID)) {
+ error_setg(errp, "cssid %hhx not valid for %s devices",
+ bus_id.cssid,
+ (is_virtio ? "virtio" : "non-virtio"));
return NULL;
}
+ }
+
+ if (bus_id.valid) {
+ if (squash_mcss) {
+ bus_id.cssid = channel_subsys.default_cssid;
+ } else if (!channel_subsys.css[bus_id.cssid]) {
+ css_create_css_image(bus_id.cssid, false);
+ }
+
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;
+ } else if (squash_mcss || is_virtio) {
+ bus_id.cssid = channel_subsys.default_cssid;
+
if (!css_find_free_subch_and_devno(bus_id.cssid, &bus_id.ssid,
&bus_id.devid, &schid, errp)) {
return NULL;
}
+ } else {
+ for (bus_id.cssid = 0; bus_id.cssid < MAX_CSSID; ++bus_id.cssid) {
+ if (bus_id.cssid == VIRTUAL_CSSID) {
+ continue;
+ }
+
+ if (!channel_subsys.css[bus_id.cssid]) {
+ css_create_css_image(bus_id.cssid, false);
+ }
+
+ if (css_find_free_subch_and_devno(bus_id.cssid, &bus_id.ssid,
+ &bus_id.devid, &schid,
+ NULL)) {
+ break ;
+ }
+ if (bus_id.cssid == MAX_CSSID) {
+ error_setg(errp, "Virtual channel subsystem is full!");
+ return NULL;
+ }
+ }
}

sch = g_malloc0(sizeof(*sch));
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index cd007ca..735d66d 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -136,10 +136,16 @@ static void ccw_init(MachineState *machine)
kvm_s390_enable_css_support(s390_cpu_addr2state(0));
}
/*
- * Create virtual css and set it as default so that non mcss-e
- * enabled guests only see virtio devices.
+ * Non mcss-e enabled guests only see the devices from the default
+ * css, which is determined by the value of the squash_mcss property.
+ * Note: we must not squash non virtio devices to css 0xFE, since
+ * it's reserved for virtio devices only.
*/
- ret = css_create_css_image(VIRTUAL_CSSID, true);
+ if (css_bus->squash_mcss) {
+ ret = css_create_css_image(0, true);
+ } else {
+ ret = css_create_css_image(VIRTUAL_CSSID, true);
+ }
assert(ret == 0);

/* Create VirtIO network adapters */
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index e7167e3..4e386e9 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -680,9 +680,13 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
VirtIOCCWDeviceClass *k = VIRTIO_CCW_DEVICE_GET_CLASS(dev);
CcwDevice *ccw_dev = CCW_DEVICE(dev);
CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
- SubchDev *sch = css_create_virtual_sch(ccw_dev->devno, errp);
+ DeviceState *parent = DEVICE(ccw_dev);
+ BusState *qbus = qdev_get_parent_bus(parent);
+ VirtualCssBus *cbus = VIRTUAL_CSS_BUS(qbus);
+ SubchDev *sch;
Error *err = NULL;

+ sch = css_create_sch(ccw_dev->devno, true, cbus->squash_mcss, errp);
if (!sch) {
return;
}
diff --git a/include/hw/s390x/css-bridge.h b/include/hw/s390x/css-bridge.h
index 5a0203b..cf08604 100644
--- a/include/hw/s390x/css-bridge.h
+++ b/include/hw/s390x/css-bridge.h
@@ -28,6 +28,7 @@ typedef struct VirtualCssBridge {
/* virtual css bus type */
typedef struct VirtualCssBus {
BusState parent_obj;
+ bool squash_mcss;
} VirtualCssBus;

#define TYPE_VIRTUAL_CSS_BUS "virtual-css-bus"
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index 868c6c7..a8bf1db 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -190,16 +190,25 @@ extern PropertyInfo css_devid_ro_propinfo;
/**
* Create a subchannel for the given bus id.
*
- * If @p bus_id is valid, verify that it uses the virtual channel
- * subsystem id and is not already in use, and find a free subchannel
- * id for it. If @p bus_id is not valid, find a free subchannel id and
- * device number across all subchannel sets. If either of the former
- * actions succeed, 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.
+ * If @p bus_id is valid, and @p squash_mcss is true, verify that it is
+ * not already in use in the default css, and find a free devno from the
+ * default css image for it.
+ * If @p bus_id is valid, and @p squash_mcss is false, verify that it is
+ * not already in use, and find a free devno for it.
+ * If @p bus_id is not valid, and if either @p squash_mcss or @p is_virtio
+ * is true, find a free subchannel id and device number across all
+ * subchannel sets from the default css image.
+ * If @p bus_id is not valid, and if both @p squash_mcss and @p is_virtio
+ * are false, find a non-full css image and find a free subchannel id and
+ * device number across all subchannel sets from it.
+ *
+ * If either of the former actions succeed, 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_virtual_sch(CssDevId bus_id, Error **errp);
+SubchDev *css_create_sch(CssDevId bus_id, bool is_virtio, bool squash_mcss,
+ Error **errp);
#endif
--
2.10.2