The branch main has been updated by royger: URL: https://cgit.FreeBSD.org/src/commit/?id=ff73b1d69b90e33e18e60a10383b75058c7639c1
commit ff73b1d69b90e33e18e60a10383b75058c7639c1 Author: Elliott Mitchell <[email protected]> AuthorDate: 2021-05-11 19:05:03 +0000 Commit: Roger Pau Monné <[email protected]> CommitDate: 2023-04-14 13:58:51 +0000 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 --- sys/x86/xen/xen_intr.c | 41 ++++++++++++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 7 deletions(-) diff --git a/sys/x86/xen/xen_intr.c b/sys/x86/xen/xen_intr.c index cf20f2cdcbf8..b3996e6cf1aa 100644 --- a/sys/x86/xen/xen_intr.c +++ b/sys/x86/xen/xen_intr.c @@ -73,6 +73,16 @@ __FBSDID("$FreeBSD$"); static MALLOC_DEFINE(M_XENINTR, "xen_intr", "Xen Interrupt Services"); +/* + * Lock for x86-related structures. Notably modifying + * xen_intr_auto_vector_count, and allocating interrupts require this lock be + * held. + * + * ->xi_type == EVTCHN_TYPE_UNBOUND indicates a xenisrc is under control of + * this lock and operations require it be held. + */ +static struct mtx xen_intr_x86_lock; + static u_int first_evtchn_irq; /** @@ -160,6 +170,16 @@ struct pic xen_intr_pic = { .pic_assign_cpu = xen_intr_pic_assign_cpu, }; +/* + * Lock for interrupt core data. + * + * Modifying xen_intr_port_to_isrc[], or isrc->xi_port (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. + * + * Acquire/release operations for isrc->xi_refcount require this lock be held. + */ 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]; @@ -274,7 +294,7 @@ xen_intr_find_unused_isrc(enum evtchn_type type) { 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; @@ -317,10 +337,10 @@ xen_intr_alloc_isrc(enum evtchn_type type) unsigned int vector; int error; - mtx_lock(&xen_intr_isrc_lock); + mtx_lock(&xen_intr_x86_lock); isrc = xen_intr_find_unused_isrc(type); if (isrc != NULL) { - mtx_unlock(&xen_intr_isrc_lock); + mtx_unlock(&xen_intr_x86_lock); return (isrc); } @@ -329,7 +349,7 @@ xen_intr_alloc_isrc(enum evtchn_type type) warned = 1; printf("%s: Xen interrupts exhausted.\n", __func__); } - mtx_unlock(&xen_intr_isrc_lock); + mtx_unlock(&xen_intr_x86_lock); return (NULL); } @@ -339,7 +359,7 @@ xen_intr_alloc_isrc(enum evtchn_type type) 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_intsrc.is_pic = &xen_intr_pic; isrc->xi_vector = vector; @@ -383,11 +403,16 @@ xen_intr_release_isrc(struct xenisrc *isrc) xen_intr_port_to_isrc[isrc->xi_port] = NULL; } + /* not reachable from xen_intr_port_to_isrc[], unlock */ + mtx_unlock(&xen_intr_isrc_lock); + isrc->xi_cpu = 0; - isrc->xi_type = EVTCHN_TYPE_UNBOUND; isrc->xi_port = INVALID_EVTCHN; 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); } @@ -634,6 +659,8 @@ xen_intr_init(void *dummy __unused) 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.
