vfio-ccw: add some logging

Usually, the common I/O layer logs various things into the s390
cio debug feature, which has been very helpful in the past when
looking at crash dumps. As vfio-ccw devices unbind from the
standard I/O subchannel driver, we lose some information there.

Let's introduce some vfio-ccw debug features and log some things
there. (Unfortunately we cannot reuse the cio debug feature from
a module.)

Message-Id: <20190816151505.9853-2-cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 9208c0e..45e792f 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -27,6 +27,9 @@ struct workqueue_struct *vfio_ccw_work_q;
 static struct kmem_cache *vfio_ccw_io_region;
 static struct kmem_cache *vfio_ccw_cmd_region;
 
+debug_info_t *vfio_ccw_debug_msg_id;
+debug_info_t *vfio_ccw_debug_trace_id;
+
 /*
  * Helpers
  */
@@ -164,6 +167,9 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
        if (ret)
                goto out_disable;
 
+       VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
+                          sch->schid.cssid, sch->schid.ssid,
+                          sch->schid.sch_no);
        return 0;
 
 out_disable:
@@ -194,6 +200,9 @@ static int vfio_ccw_sch_remove(struct subchannel *sch)
        kfree(private->cp.guest_cp);
        kfree(private);
 
+       VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
+                          sch->schid.cssid, sch->schid.ssid,
+                          sch->schid.sch_no);
        return 0;
 }
 
@@ -263,13 +272,46 @@ static struct css_driver vfio_ccw_sch_driver = {
        .sch_event = vfio_ccw_sch_event,
 };
 
+static int __init vfio_ccw_debug_init(void)
+{
+       vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
+                                              11 * sizeof(long));
+       if (!vfio_ccw_debug_msg_id)
+               goto out_unregister;
+       debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
+       debug_set_level(vfio_ccw_debug_msg_id, 2);
+       vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
+       if (!vfio_ccw_debug_trace_id)
+               goto out_unregister;
+       debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
+       debug_set_level(vfio_ccw_debug_trace_id, 2);
+       return 0;
+
+out_unregister:
+       debug_unregister(vfio_ccw_debug_msg_id);
+       debug_unregister(vfio_ccw_debug_trace_id);
+       return -1;
+}
+
+static void vfio_ccw_debug_exit(void)
+{
+       debug_unregister(vfio_ccw_debug_msg_id);
+       debug_unregister(vfio_ccw_debug_trace_id);
+}
+
 static int __init vfio_ccw_sch_init(void)
 {
-       int ret = -ENOMEM;
+       int ret;
+
+       ret = vfio_ccw_debug_init();
+       if (ret)
+               return ret;
 
        vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
-       if (!vfio_ccw_work_q)
-               return -ENOMEM;
+       if (!vfio_ccw_work_q) {
+               ret = -ENOMEM;
+               goto out_err;
+       }
 
        vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
                                        sizeof(struct ccw_io_region), 0,
@@ -298,6 +340,7 @@ out_err:
        kmem_cache_destroy(vfio_ccw_cmd_region);
        kmem_cache_destroy(vfio_ccw_io_region);
        destroy_workqueue(vfio_ccw_work_q);
+       vfio_ccw_debug_exit();
        return ret;
 }
 
@@ -308,6 +351,7 @@ static void __exit vfio_ccw_sch_exit(void)
        kmem_cache_destroy(vfio_ccw_io_region);
        kmem_cache_destroy(vfio_ccw_cmd_region);
        destroy_workqueue(vfio_ccw_work_q);
+       vfio_ccw_debug_exit();
 }
 module_init(vfio_ccw_sch_init);
 module_exit(vfio_ccw_sch_exit);

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 49d9d3d..4a1e727 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -37,9 +37,14 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
                goto out;
        }
 
+       VFIO_CCW_TRACE_EVENT(5, "stIO");
+       VFIO_CCW_TRACE_EVENT(5, dev_name(&sch->dev));
+
        /* Issue "Start Subchannel" */
        ccode = ssch(sch->schid, orb);
 
+       VFIO_CCW_HEX_EVENT(5, &ccode, sizeof(ccode));
+
        switch (ccode) {
        case 0:
                /*
@@ -86,9 +91,14 @@ static int fsm_do_halt(struct vfio_ccw_private *private)
 
        spin_lock_irqsave(sch->lock, flags);
 
+       VFIO_CCW_TRACE_EVENT(2, "haltIO");
+       VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
+
        /* Issue "Halt Subchannel" */
        ccode = hsch(sch->schid);
 
+       VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
+
        switch (ccode) {
        case 0:
                /*
@@ -122,9 +132,14 @@ static int fsm_do_clear(struct vfio_ccw_private *private)
 
        spin_lock_irqsave(sch->lock, flags);
 
+       VFIO_CCW_TRACE_EVENT(2, "clearIO");
+       VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
+
        /* Issue "Clear Subchannel" */
        ccode = csch(sch->schid);
 
+       VFIO_CCW_HEX_EVENT(2, &ccode, sizeof(ccode));
+
        switch (ccode) {
        case 0:
                /*
@@ -149,6 +164,9 @@ static void fsm_notoper(struct vfio_ccw_private *private,
 {
        struct subchannel *sch = private->sch;
 
+       VFIO_CCW_TRACE_EVENT(2, "notoper");
+       VFIO_CCW_TRACE_EVENT(2, dev_name(&sch->dev));
+
        /*
         * TODO:
         * Probably we should send the machine check to the guest.
@@ -229,6 +247,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
        struct ccw_io_region *io_region = private->io_region;
        struct mdev_device *mdev = private->mdev;
        char *errstr = "request";
+       struct subchannel_id schid = get_schid(private);
 
        private->state = VFIO_CCW_STATE_CP_PROCESSING;
        memcpy(scsw, io_region->scsw_area, sizeof(*scsw));
@@ -239,18 +258,32 @@ static void fsm_io_request(struct vfio_ccw_private *private,
                /* Don't try to build a cp if transport mode is specified. */
                if (orb->tm.b) {
                        io_region->ret_code = -EOPNOTSUPP;
+                       VFIO_CCW_MSG_EVENT(2,
+                                          "%pUl (%x.%x.%04x): transport mode\n",
+                                          mdev_uuid(mdev), schid.cssid,
+                                          schid.ssid, schid.sch_no);
                        errstr = "transport mode";
                        goto err_out;
                }
                io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
                                              orb);
                if (io_region->ret_code) {
+                       VFIO_CCW_MSG_EVENT(2,
+                                          "%pUl (%x.%x.%04x): cp_init=%d\n",
+                                          mdev_uuid(mdev), schid.cssid,
+                                          schid.ssid, schid.sch_no,
+                                          io_region->ret_code);
                        errstr = "cp init";
                        goto err_out;
                }
 
                io_region->ret_code = cp_prefetch(&private->cp);
                if (io_region->ret_code) {
+                       VFIO_CCW_MSG_EVENT(2,
+                                          "%pUl (%x.%x.%04x): cp_prefetch=%d\n",
+                                          mdev_uuid(mdev), schid.cssid,
+                                          schid.ssid, schid.sch_no,
+                                          io_region->ret_code);
                        errstr = "cp prefetch";
                        cp_free(&private->cp);
                        goto err_out;
@@ -259,23 +292,36 @@ static void fsm_io_request(struct vfio_ccw_private *private,
                /* Start channel program and wait for I/O interrupt. */
                io_region->ret_code = fsm_io_helper(private);
                if (io_region->ret_code) {
+                       VFIO_CCW_MSG_EVENT(2,
+                                          "%pUl (%x.%x.%04x): fsm_io_helper=%d\n",
+                                          mdev_uuid(mdev), schid.cssid,
+                                          schid.ssid, schid.sch_no,
+                                          io_region->ret_code);
                        errstr = "cp fsm_io_helper";
                        cp_free(&private->cp);
                        goto err_out;
                }
                return;
        } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
+               VFIO_CCW_MSG_EVENT(2,
+                                  "%pUl (%x.%x.%04x): halt on io_region\n",
+                                  mdev_uuid(mdev), schid.cssid,
+                                  schid.ssid, schid.sch_no);
                /* halt is handled via the async cmd region */
                io_region->ret_code = -EOPNOTSUPP;
                goto err_out;
        } else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
+               VFIO_CCW_MSG_EVENT(2,
+                                  "%pUl (%x.%x.%04x): clear on io_region\n",
+                                  mdev_uuid(mdev), schid.cssid,
+                                  schid.ssid, schid.sch_no);
                /* clear is handled via the async cmd region */
                io_region->ret_code = -EOPNOTSUPP;
                goto err_out;
        }
 
 err_out:
-       trace_vfio_ccw_io_fctl(scsw->cmd.fctl, get_schid(private),
+       trace_vfio_ccw_io_fctl(scsw->cmd.fctl, schid,
                               io_region->ret_code, errstr);
 }
 
@@ -308,6 +354,9 @@ static void fsm_irq(struct vfio_ccw_private *private,
 {
        struct irb *irb = this_cpu_ptr(&cio_irb);
 
+       VFIO_CCW_TRACE_EVENT(6, "IRQ");
+       VFIO_CCW_TRACE_EVENT(6, dev_name(&private->sch->dev));
+
        memcpy(&private->irb, irb, sizeof(*irb));
 
        queue_work(vfio_ccw_work_q, &private->io_work);

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 5eb6111..f0d71ab 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -124,6 +124,11 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
        private->mdev = mdev;
        private->state = VFIO_CCW_STATE_IDLE;
 
+       VFIO_CCW_MSG_EVENT(2, "mdev %pUl, sch %x.%x.%04x: create\n",
+                          mdev_uuid(mdev), private->sch->schid.cssid,
+                          private->sch->schid.ssid,
+                          private->sch->schid.sch_no);
+
        return 0;
 }
 
@@ -132,6 +137,11 @@ static int vfio_ccw_mdev_remove(struct mdev_device *mdev)
        struct vfio_ccw_private *private =
                dev_get_drvdata(mdev_parent_dev(mdev));
 
+       VFIO_CCW_MSG_EVENT(2, "mdev %pUl, sch %x.%x.%04x: remove\n",
+                          mdev_uuid(mdev), private->sch->schid.cssid,
+                          private->sch->schid.ssid,
+                          private->sch->schid.sch_no);
+
        if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
            (private->state != VFIO_CCW_STATE_STANDBY)) {
                if (!vfio_ccw_sch_quiesce(private->sch))

diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index f1092c3..bbe9bab 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -17,6 +17,7 @@
 #include <linux/eventfd.h>
 #include <linux/workqueue.h>
 #include <linux/vfio_ccw.h>
+#include <asm/debug.h>
 
 #include "css.h"
 #include "vfio_ccw_cp.h"
@@ -139,4 +140,20 @@ static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private,
 
 extern struct workqueue_struct *vfio_ccw_work_q;
 
+
+/* s390 debug feature, similar to base cio */
+extern debug_info_t *vfio_ccw_debug_msg_id;
+extern debug_info_t *vfio_ccw_debug_trace_id;
+
+#define VFIO_CCW_TRACE_EVENT(imp, txt) \
+               debug_text_event(vfio_ccw_debug_trace_id, imp, txt)
+
+#define VFIO_CCW_MSG_EVENT(imp, args...) \
+               debug_sprintf_event(vfio_ccw_debug_msg_id, imp, ##args)
+
+static inline void VFIO_CCW_HEX_EVENT(int level, void *data, int length)
+{
+       debug_event(vfio_ccw_debug_trace_id, level, data, length);
+}
+
 #endif