[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 1/1] evtchn: make EVTCHNOP_reset suitable for kexec
On 30/07/14 14:26, Vitaly Kuznetsov wrote: > It would be nice to allow guests to close all event channels in > ABI-agnostic way in case of kexec/kdump. EVTCHNOP_reset looks suitable > for this purpose. However control blocks for vcpus and event array need > cleanup when FIFO ABI is being used. > > With this change a guest can simply do EVTCHNOP_reset before kexec in > both 2-level and FIFO cases. It is also important to perform store/console > channel remapping after such call. Can you add documentation to xen/include/public/event_channels.h? > The issue can also be solved by introducing a new EVTCHNOP operation but > it seems that EVTCHNOP_reset can be reused. > > [The idea was suggested by Ian Campbell, Andrew Cooper, and David Vrabel] > > Changes from v1: List changes after a --- marker so they don't end up in the final commit message. > --- a/xen/common/event_channel.c > +++ b/xen/common/event_channel.c > @@ -957,6 +957,17 @@ static long evtchn_reset(evtchn_reset_t *r) > for ( i = 0; port_is_valid(d, i); i++ ) > (void)__evtchn_close(d, i); > > + if ( (d == current->domain) && d->evtchn_fifo ) > + { > + /* > + * Guest domain called EVTCHNOP_reset with DOMID_SELF, destroying > + * FIFO event array and control blocks, resetting evtchn_port_ops to > + * evtchn_port_ops_2l. > + */ > + evtchn_fifo_destroy(d); > + evtchn_2l_init(d); You need to take d->event_lock around this if, or the guest could try to bind another event whilst the ABI is in an inconsistent state. David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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