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xen/intr: cleanup event channel number use

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Consistently use ~0 instead of 0 when clearing xenisrc structures.
0 is a valid event channel number, even though it is reserved by Xen.
Whereas ~0 is guaranteed invalid.

Reviewed by: royger
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30743
This commit is contained in:
Elliott Mitchell 2021-06-05 17:43:13 -07:00 committed by Roger Pau Monné
parent 2b2415bafa
commit 1797ff9627
1 changed files with 18 additions and 6 deletions
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24
sys/x86/xen/xen_intr.c
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@ -117,9 +117,8 @@ DPCPU_DEFINE_STATIC(struct xen_intr_pcpu_data, xen_intr_pcpu) = {
DPCPU_DECLARE(struct vcpu_info *, vcpu_info);
#define XEN_INVALID_EVTCHN 0 /* Invalid event channel */
#define is_valid_evtchn(x) ((x) != XEN_INVALID_EVTCHN)
#define INVALID_EVTCHN (~(evtchn_port_t)0) /* Invalid event channel */
#define is_valid_evtchn(x) ((uintmax_t)(x) < NR_EVENT_CHANNELS)
struct xenisrc {
struct intsrc xi_intsrc;
@ -372,7 +371,7 @@ xen_intr_release_isrc(struct xenisrc *isrc)
}
isrc->xi_cpu = 0;
isrc->xi_type = EVTCHN_TYPE_UNBOUND;
isrc->xi_port = 0;
isrc->xi_port = INVALID_EVTCHN;
isrc->xi_cookie = NULL;
mtx_unlock(&xen_intr_isrc_lock);
return (0);
@ -613,6 +612,19 @@ xen_intr_init(void *dummy __unused)
if (!xen_domain())
return (0);
_Static_assert(is_valid_evtchn(0),
"is_valid_evtchn(0) fails (unused by Xen, but valid by interface");
_Static_assert(is_valid_evtchn(NR_EVENT_CHANNELS - 1),
"is_valid_evtchn(max) fails (is a valid channel)");
_Static_assert(!is_valid_evtchn(NR_EVENT_CHANNELS),
"is_valid_evtchn(>max) fails (NOT a valid channel)");
_Static_assert(!is_valid_evtchn(~(evtchn_port_t)0),
"is_valid_evtchn(maxint) fails (overflow?)");
_Static_assert(!is_valid_evtchn(INVALID_EVTCHN),
"is_valid_evtchn(INVALID_EVTCHN) fails (must be invalid!)");
_Static_assert(!is_valid_evtchn(-1),
"is_valid_evtchn(-1) fails (negative are invalid)");
mtx_init(&xen_intr_isrc_lock, "xen-irq-lock", NULL, MTX_DEF);
/*
@ -769,7 +781,7 @@ xen_intr_resume(struct pic *unused, bool suspend_cancelled)
vector = first_evtchn_irq + isrc_idx;
isrc = (struct xenisrc *)intr_lookup_source(vector);
if (isrc != NULL) {
isrc->xi_port = 0;
isrc->xi_port = INVALID_EVTCHN;
switch (isrc->xi_type) {
case EVTCHN_TYPE_IPI:
xen_rebind_ipi(isrc);
@ -1292,7 +1304,7 @@ int
xen_intr_get_evtchn_from_port(evtchn_port_t port, xen_intr_handle_t *handlep)
{
if (!is_valid_evtchn(port) || port >= NR_EVENT_CHANNELS)
if (!is_valid_evtchn(port))
return (EINVAL);
if (handlep == NULL) {