diff options
Diffstat (limited to 'system/xen/xsa/xsa344-4.13-1.patch')
| -rw-r--r-- | system/xen/xsa/xsa344-4.13-1.patch | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa344-4.13-1.patch b/system/xen/xsa/xsa344-4.13-1.patch new file mode 100644 index 0000000000..d8e9b3f43f --- /dev/null +++ b/system/xen/xsa/xsa344-4.13-1.patch @@ -0,0 +1,130 @@ +From: Jan Beulich <jbeulich@suse.com> +Subject: evtchn: arrange for preemption in evtchn_destroy() + +Especially closing of fully established interdomain channels can take +quite some time, due to the locking involved. Therefore we shouldn't +assume we can clean up still active ports all in one go. Besides adding +the necessary preemption check, also avoid pointlessly starting from +(or now really ending at) 0; 1 is the lowest numbered port which may +need closing. + +Since we're now reducing ->valid_evtchns, free_xen_event_channel(), +and (at least to be on the safe side) notify_via_xen_event_channel() +need to cope with attempts to close / unbind from / send through already +closed (and no longer valid, as per port_is_valid()) ports. + +This is part of XSA-344. + +Signed-off-by: Jan Beulich <jbeulich@suse.com> +Acked-by: Julien Grall <jgrall@amazon.com> +Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> + +--- a/xen/common/domain.c ++++ b/xen/common/domain.c +@@ -770,12 +770,14 @@ int domain_kill(struct domain *d) + return domain_kill(d); + d->is_dying = DOMDYING_dying; + argo_destroy(d); +- evtchn_destroy(d); + gnttab_release_mappings(d); + vnuma_destroy(d->vnuma); + domain_set_outstanding_pages(d, 0); + /* fallthrough */ + case DOMDYING_dying: ++ rc = evtchn_destroy(d); ++ if ( rc ) ++ break; + rc = domain_relinquish_resources(d); + if ( rc != 0 ) + break; +--- a/xen/common/event_channel.c ++++ b/xen/common/event_channel.c +@@ -1297,7 +1297,16 @@ int alloc_unbound_xen_event_channel( + + void free_xen_event_channel(struct domain *d, int port) + { +- BUG_ON(!port_is_valid(d, port)); ++ if ( !port_is_valid(d, port) ) ++ { ++ /* ++ * Make sure ->is_dying is read /after/ ->valid_evtchns, pairing ++ * with the spin_barrier() and BUG_ON() in evtchn_destroy(). ++ */ ++ smp_rmb(); ++ BUG_ON(!d->is_dying); ++ return; ++ } + + evtchn_close(d, port, 0); + } +@@ -1309,7 +1318,17 @@ void notify_via_xen_event_channel(struct + struct domain *rd; + unsigned long flags; + +- ASSERT(port_is_valid(ld, lport)); ++ if ( !port_is_valid(ld, lport) ) ++ { ++ /* ++ * Make sure ->is_dying is read /after/ ->valid_evtchns, pairing ++ * with the spin_barrier() and BUG_ON() in evtchn_destroy(). ++ */ ++ smp_rmb(); ++ ASSERT(ld->is_dying); ++ return; ++ } ++ + lchn = evtchn_from_port(ld, lport); + + spin_lock_irqsave(&lchn->lock, flags); +@@ -1380,8 +1399,7 @@ int evtchn_init(struct domain *d, unsign + return 0; + } + +- +-void evtchn_destroy(struct domain *d) ++int evtchn_destroy(struct domain *d) + { + unsigned int i; + +@@ -1390,14 +1408,29 @@ void evtchn_destroy(struct domain *d) + spin_barrier(&d->event_lock); + + /* Close all existing event channels. */ +- for ( i = 0; port_is_valid(d, i); i++ ) ++ for ( i = d->valid_evtchns; --i; ) ++ { + evtchn_close(d, i, 0); + ++ /* ++ * Avoid preempting when called from domain_create()'s error path, ++ * and don't check too often (choice of frequency is arbitrary). ++ */ ++ if ( i && !(i & 0x3f) && d->is_dying != DOMDYING_dead && ++ hypercall_preempt_check() ) ++ { ++ write_atomic(&d->valid_evtchns, i); ++ return -ERESTART; ++ } ++ } ++ + ASSERT(!d->active_evtchns); + + clear_global_virq_handlers(d); + + evtchn_fifo_destroy(d); ++ ++ return 0; + } + + +--- a/xen/include/xen/sched.h ++++ b/xen/include/xen/sched.h +@@ -136,7 +136,7 @@ struct evtchn + } __attribute__((aligned(64))); + + int evtchn_init(struct domain *d, unsigned int max_port); +-void evtchn_destroy(struct domain *d); /* from domain_kill */ ++int evtchn_destroy(struct domain *d); /* from domain_kill */ + void evtchn_destroy_final(struct domain *d); /* from complete_domain_destroy */ + + struct waitqueue_vcpu; |