[PATCH v4 for Xen 4.6 1/4] xen: enable per-VCPU parameter settings for RTDS scheduler

[Chong Li <lichong659@gmail.com>]

Add XEN_DOMCTL_SCHEDOP_getvcpuinfo and _putvcpuinfo hypercalls
to independently get and set the scheduling parameters of each
vCPU of a domain

Signed-off-by: Chong Li <chong.li@wustl.edu>
Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
Signed-off-by: Sisu Xi <xisisu@gmail.com>

---
Changes on PATCH v3:

1) Remove struct xen_domctl_schedparam_t.

2) Change struct xen_domctl_scheduler_op.

3) Check if period/budget is within a validated range

CC: <dario.faggioli@citrix.com>
CC: <george.dunlap@eu.citrix.com>
CC: <dgolomb@seas.upenn.edu>
CC: <mengxu@cis.upenn.edu>
CC: <jbeulich@suse.com>
CC: <lichong659@gmail.com>
---
 xen/common/domctl.c         |   3 ++
 xen/common/sched_rt.c       | 100 +++++++++++++++++++++++++++++++++++++++++---
 xen/common/schedule.c       |  18 ++++++--
 xen/include/public/domctl.h |  61 +++++++++++++++++++--------
 4 files changed, 155 insertions(+), 27 deletions(-)

diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 2a2d203..349f68b 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -839,6 +839,9 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
 
     case XEN_DOMCTL_scheduler_op:
         ret = sched_adjust(d, &op->u.scheduler_op);
+        if ( ret == -ERESTART )
+            ret = hypercall_create_continuation(
+                __HYPERVISOR_domctl, "h", u_domctl);
         copyback = 1;
         break;
 
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 4372486..fed9e09 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -78,7 +78,6 @@
  *    vcpu_insert, vcpu_remove, context_saved, __runq_insert
  */
 
-
 /*
  * Default parameters:
  * Period and budget in default is 10 and 4 ms, respectively
@@ -86,6 +85,18 @@
 #define RTDS_DEFAULT_PERIOD     (MICROSECS(10000))
 #define RTDS_DEFAULT_BUDGET     (MICROSECS(4000))
 
+/*
+ * Max period: max delta of time type
+ * Min period: 100 us, considering the scheduling overhead
+ */
+#define RTDS_MAX_PERIOD     (STIME_DELTA_MAX)
+#define RTDS_MIN_PERIOD     (MICROSECS(100))
+
+/*
+ * Min budget: 100 us
+ */
+#define RTDS_MIN_BUDGET     (MICROSECS(100))
+
 #define UPDATE_LIMIT_SHIFT      10
 #define MAX_SCHEDULE            (MILLISECS(1))
 /*
@@ -1137,14 +1148,17 @@ rt_dom_cntl(
     struct list_head *iter;
     unsigned long flags;
     int rc = 0;
+    int warn = 0;
+    xen_domctl_schedparam_vcpu_t local_sched;
+    s_time_t period, budget;
+    unsigned int index;
 
     switch ( op->cmd )
     {
-    case XEN_DOMCTL_SCHEDOP_getinfo:
+    case XEN_DOMCTL_SCHEDOP_getinfo: /* return the default parameters */
         spin_lock_irqsave(&prv->lock, flags);
-        svc = list_entry(sdom->vcpu.next, struct rt_vcpu, sdom_elem);
-        op->u.rtds.period = svc->period / MICROSECS(1); /* transfer to us */
-        op->u.rtds.budget = svc->budget / MICROSECS(1);
+        op->u.rtds.period = RTDS_DEFAULT_PERIOD / MICROSECS(1); /* transfer to us */
+        op->u.rtds.budget = RTDS_DEFAULT_BUDGET / MICROSECS(1);
         spin_unlock_irqrestore(&prv->lock, flags);
         break;
     case XEN_DOMCTL_SCHEDOP_putinfo:
@@ -1162,8 +1176,82 @@ rt_dom_cntl(
         }
         spin_unlock_irqrestore(&prv->lock, flags);
         break;
+    case XEN_DOMCTL_SCHEDOP_getvcpuinfo:
+        spin_lock_irqsave(&prv->lock, flags);
+        for ( index = 0; index < op->u.v.nr_vcpus; index++ )
+        {
+            if ( copy_from_guest_offset(&local_sched,
+                          op->u.v.vcpus, index, 1) )
+            {
+                rc = -EFAULT;
+                break;
+            }
+            if ( local_sched.vcpuid >= d->max_vcpus ||
+                          d->vcpu[local_sched.vcpuid] == NULL )
+            {
+                rc = -EINVAL;
+                break;
+            }
+            svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
+
+            local_sched.s.rtds.budget = svc->budget / MICROSECS(1);
+            local_sched.s.rtds.period = svc->period / MICROSECS(1);
+
+            if ( __copy_to_guest_offset(op->u.v.vcpus, index,
+                    &local_sched, 1) )
+            {
+                rc = -EFAULT;
+                break;
+            }
+            if( hypercall_preempt_check() )
+            {
+                rc = -ERESTART;
+                break;
+            }
+        }
+        spin_unlock_irqrestore(&prv->lock, flags);
+        break;
+    case XEN_DOMCTL_SCHEDOP_putvcpuinfo:
+        spin_lock_irqsave(&prv->lock, flags);
+        for( index = 0; index < op->u.v.nr_vcpus; index++ )
+        {
+            if ( copy_from_guest_offset(&local_sched,
+                          op->u.v.vcpus, index, 1) )
+            {
+                rc = -EFAULT;
+                break;
+            }
+            if ( local_sched.vcpuid >= d->max_vcpus ||
+                          d->vcpu[local_sched.vcpuid] == NULL )
+            {
+                rc = -EINVAL;
+                break;
+            }
+            svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
+            period = MICROSECS(local_sched.s.rtds.period);
+            budget = MICROSECS(local_sched.s.rtds.budget);
+            if ( period < MICROSECS(10) || period > RTDS_MAX_PERIOD ||
+                          budget < MICROSECS(10) || budget > period )
+            {
+                rc = -EINVAL;
+                break;
+            }
+            if ( period < RTDS_MIN_PERIOD || budget < RTDS_MIN_BUDGET )
+                warn = 1;
+
+            svc->period = period;
+            svc->budget = budget;
+            if( hypercall_preempt_check() )
+            {
+                rc = -ERESTART;
+                break;
+            }
+        }
+        spin_unlock_irqrestore(&prv->lock, flags);
+        break;
     }
-
+    if ( rc == 0 && warn == 1 ) /* print warning in libxl */
+        rc = 1;
     return rc;
 }
 
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index ecf1545..886e1b5 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1052,10 +1052,22 @@ long sched_adjust(struct domain *d, struct xen_domctl_scheduler_op *op)
     if ( ret )
         return ret;
 
-    if ( (op->sched_id != DOM2OP(d)->sched_id) ||
-         ((op->cmd != XEN_DOMCTL_SCHEDOP_putinfo) &&
-          (op->cmd != XEN_DOMCTL_SCHEDOP_getinfo)) )
+    if ( op->sched_id != DOM2OP(d)->sched_id )
         return -EINVAL;
+    else
+        switch ( op->cmd )
+        {
+        case XEN_DOMCTL_SCHEDOP_putinfo:
+            break;
+        case XEN_DOMCTL_SCHEDOP_getinfo:
+            break;
+        case XEN_DOMCTL_SCHEDOP_putvcpuinfo:
+            break;
+        case XEN_DOMCTL_SCHEDOP_getvcpuinfo:
+            break;
+        default:
+            return -EINVAL;
+        }
 
     /* NB: the pluggable scheduler code needs to take care
      * of locking by itself. */
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index bc45ea5..bfb432f 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -330,31 +330,56 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_max_vcpus_t);
 #define XEN_SCHEDULER_ARINC653 7
 #define XEN_SCHEDULER_RTDS     8
 
+typedef struct xen_domctl_sched_sedf {
+    uint64_aligned_t period;
+    uint64_aligned_t slice;
+    uint64_aligned_t latency;
+    uint32_t extratime;
+    uint32_t weight;
+} xen_domctl_sched_sedf_t;
+
+typedef struct xen_domctl_sched_credit {
+    uint16_t weight;
+    uint16_t cap;
+} xen_domctl_sched_credit_t;
+
+typedef struct xen_domctl_sched_credit2 {
+    uint16_t weight;
+} xen_domctl_sched_credit2_t;
+
+typedef struct xen_domctl_sched_rtds {
+    uint32_t period;
+    uint32_t budget;
+} xen_domctl_sched_rtds_t;
+
+typedef struct xen_domctl_schedparam_vcpu {
+    union {
+        xen_domctl_sched_credit_t credit;
+        xen_domctl_sched_credit2_t credit2;
+        xen_domctl_sched_rtds_t rtds;
+    } s;
+    uint16_t vcpuid;
+    uint16_t padding;
+} xen_domctl_schedparam_vcpu_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_schedparam_vcpu_t);
+
 /* Set or get info? */
 #define XEN_DOMCTL_SCHEDOP_putinfo 0
 #define XEN_DOMCTL_SCHEDOP_getinfo 1
+#define XEN_DOMCTL_SCHEDOP_putvcpuinfo 2
+#define XEN_DOMCTL_SCHEDOP_getvcpuinfo 3
 struct xen_domctl_scheduler_op {
     uint32_t sched_id;  /* XEN_SCHEDULER_* */
     uint32_t cmd;       /* XEN_DOMCTL_SCHEDOP_* */
     union {
-        struct xen_domctl_sched_sedf {
-            uint64_aligned_t period;
-            uint64_aligned_t slice;
-            uint64_aligned_t latency;
-            uint32_t extratime;
-            uint32_t weight;
-        } sedf;
-        struct xen_domctl_sched_credit {
-            uint16_t weight;
-            uint16_t cap;
-        } credit;
-        struct xen_domctl_sched_credit2 {
-            uint16_t weight;
-        } credit2;
-        struct xen_domctl_sched_rtds {
-            uint32_t period;
-            uint32_t budget;
-        } rtds;
+        xen_domctl_sched_sedf_t sedf;
+        xen_domctl_sched_credit_t credit;
+        xen_domctl_sched_credit2_t credit2;
+        xen_domctl_sched_rtds_t rtds;
+        struct {
+            XEN_GUEST_HANDLE_64(xen_domctl_schedparam_vcpu_t) vcpus;
+            uint16_t nr_vcpus;
+        } v;
     } u;
 };
 typedef struct xen_domctl_scheduler_op xen_domctl_scheduler_op_t;
-- 
1.9.1