| Message ID | 20231121094953.22430-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Mini-OS: preparations for 9pfs in xenstore-stubdom | expand |
Juergen Gross, le mar. 21 nov. 2023 10:49:50 +0100, a ecrit: > Get the own domid via creation of a temporary event channel. There is > no "official" way to read the own domid in PV guests, so use the event > channel interface to get it: > > - allocate an unbound event channel specifying DOMID_SELF for the > other end > > - read the event channel status which will contain the own domid in > unbound.dom > > - close the event channel > > Signed-off-by: Juergen Gross <jgross@suse.com Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Thanks! > --- > V2: > - new patch > V3: > - rename function to get_domid() (Julien Grall) > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > events.c | 33 +++++++++++++++++++++++++++++++++ > include/lib.h | 3 +++ > 2 files changed, 36 insertions(+) > > diff --git a/events.c b/events.c > index cdae90f4..4683e8e1 100644 > --- a/events.c > +++ b/events.c > @@ -261,6 +261,39 @@ int evtchn_get_peercontext(evtchn_port_t local_port, char *ctx, int size) > return rc; > } > > +/* Replace below when a hypercall is available to get the domid. */ > +domid_t get_domid(void) > +{ > + int rc; > + domid_t domid = DOMID_INVALID; > + evtchn_alloc_unbound_t op; > + struct evtchn_status status; > + struct evtchn_close close; > + > + op.dom = DOMID_SELF; > + op.remote_dom = DOMID_SELF; > + rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &op); > + if ( rc ) > + { > + printk("ERROR: alloc_unbound failed with rc=%d", rc); > + return domid; > + } > + > + status.dom = DOMID_SELF; > + status.port = op.port; > + rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status); > + if ( rc ) > + printk("ERROR: EVTCHNOP_status failed with rc=%d", rc); > + else > + domid = status.u.unbound.dom; > + > + close.port = op.port; > + rc = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); > + if ( rc ) > + printk("WARN: close_port %d failed rc=%d. ignored\n", close.port, rc); > + > + return domid; > +} > > /* > * Local variables: > diff --git a/include/lib.h b/include/lib.h > index fd8c36de..dd68985a 100644 > --- a/include/lib.h > +++ b/include/lib.h > @@ -154,6 +154,9 @@ do { \ > /* Consistency check as much as possible. */ > void sanity_check(void); > > +/* Get own domid. */ > +domid_t get_domid(void); > + > #ifdef HAVE_LIBC > extern struct wait_queue_head event_queue; > > -- > 2.35.3 >
diff --git a/events.c b/events.c index cdae90f4..4683e8e1 100644 --- a/events.c +++ b/events.c @@ -261,6 +261,39 @@ int evtchn_get_peercontext(evtchn_port_t local_port, char *ctx, int size) return rc; } +/* Replace below when a hypercall is available to get the domid. */ +domid_t get_domid(void) +{ + int rc; + domid_t domid = DOMID_INVALID; + evtchn_alloc_unbound_t op; + struct evtchn_status status; + struct evtchn_close close; + + op.dom = DOMID_SELF; + op.remote_dom = DOMID_SELF; + rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &op); + if ( rc ) + { + printk("ERROR: alloc_unbound failed with rc=%d", rc); + return domid; + } + + status.dom = DOMID_SELF; + status.port = op.port; + rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status); + if ( rc ) + printk("ERROR: EVTCHNOP_status failed with rc=%d", rc); + else + domid = status.u.unbound.dom; + + close.port = op.port; + rc = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); + if ( rc ) + printk("WARN: close_port %d failed rc=%d. ignored\n", close.port, rc); + + return domid; +} /* * Local variables: diff --git a/include/lib.h b/include/lib.h index fd8c36de..dd68985a 100644 --- a/include/lib.h +++ b/include/lib.h @@ -154,6 +154,9 @@ do { \ /* Consistency check as much as possible. */ void sanity_check(void); +/* Get own domid. */ +domid_t get_domid(void); + #ifdef HAVE_LIBC extern struct wait_queue_head event_queue;