xen/intr: split xen_intr_isrc_lock uses
There are actually several distinct locking domains in xen_intr.c, but all were sharing the same lock. Both xen_intr_port_to_isrc[] and the x86 interrupt structures needed protection. Split these two apart as a precursor to splitting the architecture portions off the file. Reviewed by: royger Differential Revision: https://reviews.freebsd.org/D30726
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@ -73,6 +73,16 @@ __FBSDID("$FreeBSD$");
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static MALLOC_DEFINE(M_XENINTR, "xen_intr", "Xen Interrupt Services");
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/*
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* Lock for x86-related structures. Notably modifying
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* xen_intr_auto_vector_count, and allocating interrupts require this lock be
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* held.
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*
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* ->xi_type == EVTCHN_TYPE_UNBOUND indicates a xenisrc is under control of
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* this lock and operations require it be held.
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*/
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static struct mtx xen_intr_x86_lock;
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static u_int first_evtchn_irq;
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/**
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@ -160,6 +170,16 @@ struct pic xen_intr_pic = {
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.pic_assign_cpu = xen_intr_pic_assign_cpu,
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};
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/*
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* Lock for interrupt core data.
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*
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* Modifying xen_intr_port_to_isrc[], or isrc->xi_port (implies the former)
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* requires this lock be held. Any time this lock is not held, the condition
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* `!xen_intr_port_to_isrc[i] || (xen_intr_port_to_isrc[i]->ix_port == i)`
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* MUST be true for all values of i which are valid indicies of the array.
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*
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* Acquire/release operations for isrc->xi_refcount require this lock be held.
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*/
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static struct mtx xen_intr_isrc_lock;
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static u_int xen_intr_auto_vector_count;
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static struct xenisrc *xen_intr_port_to_isrc[NR_EVENT_CHANNELS];
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@ -274,7 +294,7 @@ xen_intr_find_unused_isrc(enum evtchn_type type)
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{
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int isrc_idx;
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KASSERT(mtx_owned(&xen_intr_isrc_lock), ("Evtchn isrc lock not held"));
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mtx_assert(&xen_intr_x86_lock, MA_OWNED);
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for (isrc_idx = 0; isrc_idx < xen_intr_auto_vector_count; isrc_idx ++) {
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struct xenisrc *isrc;
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@ -317,10 +337,10 @@ xen_intr_alloc_isrc(enum evtchn_type type)
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unsigned int vector;
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int error;
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mtx_lock(&xen_intr_isrc_lock);
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mtx_lock(&xen_intr_x86_lock);
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isrc = xen_intr_find_unused_isrc(type);
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if (isrc != NULL) {
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mtx_unlock(&xen_intr_isrc_lock);
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mtx_unlock(&xen_intr_x86_lock);
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return (isrc);
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}
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@ -329,7 +349,7 @@ xen_intr_alloc_isrc(enum evtchn_type type)
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warned = 1;
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printf("%s: Xen interrupts exhausted.\n", __func__);
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}
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mtx_unlock(&xen_intr_isrc_lock);
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mtx_unlock(&xen_intr_x86_lock);
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return (NULL);
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}
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@ -339,7 +359,7 @@ xen_intr_alloc_isrc(enum evtchn_type type)
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KASSERT((intr_lookup_source(vector) == NULL),
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("Trying to use an already allocated vector"));
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mtx_unlock(&xen_intr_isrc_lock);
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mtx_unlock(&xen_intr_x86_lock);
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isrc = malloc(sizeof(*isrc), M_XENINTR, M_WAITOK | M_ZERO);
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isrc->xi_intsrc.is_pic = &xen_intr_pic;
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isrc->xi_vector = vector;
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@ -383,11 +403,16 @@ xen_intr_release_isrc(struct xenisrc *isrc)
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xen_intr_port_to_isrc[isrc->xi_port] = NULL;
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}
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/* not reachable from xen_intr_port_to_isrc[], unlock */
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mtx_unlock(&xen_intr_isrc_lock);
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isrc->xi_cpu = 0;
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isrc->xi_type = EVTCHN_TYPE_UNBOUND;
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isrc->xi_port = INVALID_EVTCHN;
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isrc->xi_cookie = NULL;
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mtx_unlock(&xen_intr_isrc_lock);
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mtx_lock(&xen_intr_x86_lock);
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isrc->xi_type = EVTCHN_TYPE_UNBOUND;
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mtx_unlock(&xen_intr_x86_lock);
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return (0);
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}
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@ -634,6 +659,8 @@ xen_intr_init(void *dummy __unused)
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mtx_init(&xen_intr_isrc_lock, "xen-irq-lock", NULL, MTX_DEF);
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mtx_init(&xen_intr_x86_lock, "xen-x86-table-lock", NULL, MTX_DEF);
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/*
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* Set the per-cpu mask of CPU#0 to enable all, since by default all
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* event channels are bound to CPU#0.
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