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Index: sys/xen/xen_intr.c
===================================================================
--- sys/xen/xen_intr.c
+++ sys/xen/xen_intr.c
@@ -72,6 +72,14 @@
static MALLOC_DEFINE(M_XENINTR, "xen_intr", "Xen Interrupt Services");
+/*
+ * Lock for x86-related structures. Notably modifying
+ * xen_intr_auto_vector_count, allocating/releasing interrupts require this
+ * lock to be held. This means modifying isrc->xi_type requires this lock to
+ * be held.
+ */
+static struct mtx xen_intr_x86_lock;
+
static u_int first_evtchn_irq;
/**
@@ -165,6 +173,14 @@
.pic_assign_cpu = xen_intr_assign_cpu
};
+/*
+ * Lock for interrupt core data. Notably modifying xen_intr_port_to_isrc[],
+ * or isrc->xi_port (which implies the former) requires this lock be held.
+ *
+ * Any time this lock is not held, the condition
+ * `!xen_intr_port_to_isrc[i] || (xen_intr_port_to_isrc[i]->ix_port == i)`
+ * MUST be true for all values of i which are valid indicies of the array.
+ */
static struct mtx xen_intr_isrc_lock;
static u_int xen_intr_auto_vector_count;
static struct xenisrc *xen_intr_port_to_isrc[NR_EVENT_CHANNELS];
@@ -279,7 +295,7 @@
{
int isrc_idx;
- KASSERT(mtx_owned(&xen_intr_isrc_lock), ("Evtchn isrc lock not held"));
+ mtx_assert(&xen_intr_x86_lock, MA_OWNED);
for (isrc_idx = 0; isrc_idx < xen_intr_auto_vector_count; isrc_idx ++) {
struct xenisrc *isrc;
@@ -313,13 +329,20 @@
struct xenisrc *isrc;
unsigned int vector;
- KASSERT(mtx_owned(&xen_intr_isrc_lock), ("Evtchn alloc lock not held"));
+ mtx_lock(&xen_intr_x86_lock);
+ isrc = xen_intr_find_unused_isrc(type);
+
+ if (isrc != NULL) {
+ mtx_unlock(&xen_intr_x86_lock);
+ return (isrc);
+ }
if (xen_intr_auto_vector_count > NR_EVENT_CHANNELS) {
if (!warned) {
warned = 1;
printf("%s: Event channels exhausted.\n", __func__);
}
+ mtx_unlock(&xen_intr_x86_lock);
return (NULL);
}
@@ -329,13 +352,12 @@
KASSERT((intr_lookup_source(vector) == NULL),
("Trying to use an already allocated vector"));
- mtx_unlock(&xen_intr_isrc_lock);
+ mtx_unlock(&xen_intr_x86_lock);
isrc = malloc(sizeof(*isrc), M_XENINTR, M_WAITOK | M_ZERO);
isrc->xi_arch.xai_intsrc.is_pic = &xen_intr_pic;
isrc->xi_arch.xai_vector = vector;
isrc->xi_type = type;
intr_register_source(&isrc->xi_arch.xai_intsrc);
- mtx_lock(&xen_intr_isrc_lock);
return (isrc);
}
@@ -368,11 +390,15 @@
}
xen_intr_port_to_isrc[isrc->xi_port] = NULL;
+ /* not reachable from xen_intr_port_to_isrc[], therefore unlock */
+ mtx_unlock(&xen_intr_isrc_lock);
+
isrc->xi_cpu = 0;
- isrc->xi_type = EVTCHN_TYPE_UNBOUND;
isrc->xi_port = 0;
isrc->xi_cookie = NULL;
- mtx_unlock(&xen_intr_isrc_lock);
+ mtx_lock(&xen_intr_x86_lock);
+ isrc->xi_type = EVTCHN_TYPE_UNBOUND;
+ mtx_unlock(&xen_intr_x86_lock);
return (0);
}
@@ -412,15 +438,10 @@
return (EINVAL);
}
+ isrc = xen_intr_alloc_isrc(type);
+ if (isrc == NULL)
+ return (ENOSPC);
mtx_lock(&xen_intr_isrc_lock);
- isrc = xen_intr_find_unused_isrc(type);
- if (isrc == NULL) {
- isrc = xen_intr_alloc_isrc(type);
- if (isrc == NULL) {
- mtx_unlock(&xen_intr_isrc_lock);
- return (ENOSPC);
- }
- }
isrc->xi_port = local_port;
xen_intr_port_to_isrc[local_port] = isrc;
refcount_init(&isrc->xi_refcount, 1);
@@ -618,6 +639,8 @@
mtx_init(&xen_intr_isrc_lock, "xen-irq-lock", NULL, MTX_DEF);
+ mtx_init(&xen_intr_x86_lock, "xen-x86-table-lock", NULL, MTX_DEF);
+
/*
* Set the per-cpu mask of CPU#0 to enable all, since by default all
* event channels are bound to CPU#0.

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