x86_64: allow more vCPU-s per guest

Since the shared info layout is fixed, guests are required to use
VCPUOP_register_vcpu_info prior to booting any vCPU beyond the
traditional limit of 32.

MAX_VIRT_CPUS, being an implemetation detail of the hypervisor, is no
longer being exposed in the public headers.

The tools changes are clearly incomplete (and done only so things
would
build again), and the current state of the tools (using scalar
variables all over the place to represent vCPU bitmaps) very likely
doesn't permit booting DomU-s with more than the traditional number of
vCPU-s. Testing of the extended functionality was done with Dom0 (96
vCPU-s, as well as 128 vCPU-s out of which the kernel elected - by way
of a simple kernel side patch - to use only some, resulting in a
sparse
bitmap).

ia64 changes only to make things build, and build-tested only (and the
tools part only as far as the build would go without encountering
unrelated problems in the blktap code).

Signed-off-by: Jan Beulich <jbeulich@novell.com>

1 files changed, 33 insertions, 8 deletions

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index c51fd10031..ccc709111f 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -240,10 +240,13 @@ static long evtchn_bind_virq(evtchn_bind_virq_t *bind)
     if ( virq_is_global(virq) && (vcpu != 0) )
         return -EINVAL;
 
-    if ( (vcpu < 0) || (vcpu >= ARRAY_SIZE(d->vcpu)) ||
+    if ( (vcpu < 0) || (vcpu >= d->max_vcpus) ||
          ((v = d->vcpu[vcpu]) == NULL) )
         return -ENOENT;
 
+    if ( unlikely(!v->vcpu_info) )
+        return -EAGAIN;
+
     spin_lock(&d->event_lock);
 
     if ( v->virq_to_evtchn[virq] != 0 )
@@ -273,10 +276,13 @@ static long evtchn_bind_ipi(evtchn_bind_ipi_t *bind)
     int            port, vcpu = bind->vcpu;
     long           rc = 0;
 
-    if ( (vcpu < 0) || (vcpu >= ARRAY_SIZE(d->vcpu)) ||
+    if ( (vcpu < 0) || (vcpu >= d->max_vcpus) ||
          (d->vcpu[vcpu] == NULL) )
         return -ENOENT;
 
+    if ( unlikely(!d->vcpu[vcpu]->vcpu_info) )
+        return -EAGAIN;
+
     spin_lock(&d->event_lock);
 
     if ( (port = get_free_port(d)) < 0 )
@@ -555,13 +561,13 @@ static int evtchn_set_pending(struct vcpu *v, int port)
     }
     
     /* Check if some VCPU might be polling for this event. */
-    if ( likely(bitmap_empty(d->poll_mask, MAX_VIRT_CPUS)) )
+    if ( likely(bitmap_empty(d->poll_mask, d->max_vcpus)) )
         return 0;
 
     /* Wake any interested (or potentially interested) pollers. */
-    for ( vcpuid = find_first_bit(d->poll_mask, MAX_VIRT_CPUS);
-          vcpuid < MAX_VIRT_CPUS;
-          vcpuid = find_next_bit(d->poll_mask, MAX_VIRT_CPUS, vcpuid+1) )
+    for ( vcpuid = find_first_bit(d->poll_mask, d->max_vcpus);
+          vcpuid < d->max_vcpus;
+          vcpuid = find_next_bit(d->poll_mask, d->max_vcpus, vcpuid+1) )
     {
         v = d->vcpu[vcpuid];
         if ( ((v->poll_evtchn <= 0) || (v->poll_evtchn == port)) &&
@@ -608,7 +614,7 @@ void send_guest_global_virq(struct domain *d, int virq)
 
     ASSERT(virq_is_global(virq));
 
-    if ( unlikely(d == NULL) )
+    if ( unlikely(d == NULL) || unlikely(d->vcpu == NULL) )
         return;
 
     v = d->vcpu[0];
@@ -717,9 +723,12 @@ long evtchn_bind_vcpu(unsigned int port, unsigned int vcpu_id)
     struct evtchn *chn;
     long           rc = 0;
 
-    if ( (vcpu_id >= ARRAY_SIZE(d->vcpu)) || (d->vcpu[vcpu_id] == NULL) )
+    if ( (vcpu_id >= d->max_vcpus) || (d->vcpu[vcpu_id] == NULL) )
         return -ENOENT;
 
+    if ( unlikely(!d->vcpu[vcpu_id]->vcpu_info) )
+        return -EAGAIN;
+
     spin_lock(&d->event_lock);
 
     if ( !port_is_valid(d, port) )
@@ -943,6 +952,9 @@ int alloc_unbound_xen_event_channel(
     struct domain *d = local_vcpu->domain;
     int            port;
 
+    if ( unlikely(!local_vcpu->vcpu_info) )
+        return -EAGAIN;
+
     spin_lock(&d->event_lock);
 
     if ( (port = get_free_port(d)) < 0 )
@@ -1016,6 +1028,14 @@ int evtchn_init(struct domain *d)
     if ( get_free_port(d) != 0 )
         return -EINVAL;
     evtchn_from_port(d, 0)->state = ECS_RESERVED;
+
+#if MAX_VIRT_CPUS > BITS_PER_LONG
+    d->poll_mask = xmalloc_array(unsigned long, BITS_TO_LONGS(MAX_VIRT_CPUS));
+    if ( !d->poll_mask )
+        return -ENOMEM;
+    bitmap_zero(d->poll_mask, MAX_VIRT_CPUS);
+#endif
+
     return 0;
 }
 
@@ -1044,6 +1064,11 @@ void evtchn_destroy(struct domain *d)
         d->evtchn[i] = NULL;
     }
     spin_unlock(&d->event_lock);
+
+#if MAX_VIRT_CPUS > BITS_PER_LONG
+    xfree(d->poll_mask);
+    d->poll_mask = NULL;
+#endif
 }
 
 static void domain_dump_evtchn_info(struct domain *d)