[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH 03/29] tools/xenlogd: connect to frontend
On Wed, Nov 1, 2023 at 5:34 AM Juergen Gross <jgross@xxxxxxxx> wrote: > > Add the code for connecting to frontends to xenlogd. > > Signed-off-by: Juergen Gross <jgross@xxxxxxxx> > diff --git a/tools/xenlogd/xenlogd.c b/tools/xenlogd/xenlogd.c > index 792d1026a3..da0a09a122 100644 > --- a/tools/xenlogd/xenlogd.c > +++ b/tools/xenlogd/xenlogd.c > +static void connect_device(device *device) > +{ > + unsigned int val; > + xenevtchn_port_or_error_t evtchn; 1.> + > + val = read_frontend_node_uint(device, "version", 0); > + if ( val != 1 ) > + return connect_err(device, "frontend specifies illegal version"); > + val = read_frontend_node_uint(device, "num-rings", 0); > + if ( val != 1 ) > + return connect_err(device, "frontend specifies illegal ring number"); Linux uses 2 rings (XEN_9PFS_NUM_RINGS), and it doesn't connect when max-rings is less than that. max_rings = xenbus_read_unsigned(dev->otherend, "max-rings", 0); if (max_rings < XEN_9PFS_NUM_RINGS) return -EINVAL; new_device() writes max-rings as 1. So this works for mini-os, but not Linux. I'm not requesting you to change it - just noting it. > + > + val = read_frontend_node_uint(device, "event-channel-0", 0); > + if ( val == 0 ) > + return connect_err(device, "frontend specifies illegal evtchn"); > + evtchn = xenevtchn_bind_interdomain(xe, device->domid, val); > + if ( evtchn < 0 ) > + return connect_err(device, "could not bind to event channel"); > + device->evtchn = evtchn; > + > + val = read_frontend_node_uint(device, "ring-ref0", 0); > + if ( val == 0 ) > + return connect_err(device, "frontend specifies illegal grant for > ring"); > + device->intf = xengnttab_map_grant_ref(xg, device->domid, val, > + PROT_READ | PROT_WRITE); > + if ( !device->intf ) > + return connect_err(device, "could not map interface page"); > + device->ring_order = device->intf->ring_order; > + if ( device->ring_order > 9 || device->ring_order < 1 ) > + return connect_err(device, "frontend specifies illegal ring order"); > + device->ring_size = XEN_FLEX_RING_SIZE(device->ring_order); > + device->data.in = xengnttab_map_domain_grant_refs(xg, > + 1 << > device->ring_order, > + device->domid, > + device->intf->ref, > + PROT_READ | > PROT_WRITE); > + if ( !device->data.in ) > + return connect_err(device, "could not map ring pages"); > + device->data.out = device->data.in + device->ring_size; > + > + if ( pthread_create(&device->thread, NULL, io_thread, device) ) > + return connect_err(device, "could not start I/O thread"); > + device->thread_active = true; > + > + write_backend_state(device, XenbusStateConnected); > +} > + > @@ -122,6 +669,11 @@ int main(int argc, char *argv[]) > int syslog_mask = LOG_MASK(LOG_WARNING) | LOG_MASK(LOG_ERR) | > LOG_MASK(LOG_CRIT) | LOG_MASK(LOG_ALERT) | > LOG_MASK(LOG_EMERG); > + char **watch; > + struct pollfd p[2] = { > + { .events = POLLIN, .revents = POLLIN }, Are you intentionally setting revents to enter the loop initially? Shouldn't the watch registration trigger it to fire anyway? > + { .events = POLLIN } > + }; > > umask(027); > if ( getenv("XENLOGD_VERBOSE") ) > @@ -134,9 +686,26 @@ int main(int argc, char *argv[]) > > xen_connect(); > > + if ( !xs_watch(xs, "backend/xen_9pfs", "main") ) > + do_err("xs_watch() in main thread failed"); > + p[0].fd = xs_fileno(xs); > + p[1].fd = xenevtchn_fd(xe); > + > + scan_backend(); > + > while ( !stop_me ) > { > - sleep(60); > + while ( (p[0].revents & POLLIN) && > + (watch = xs_check_watch(xs)) != NULL ) > + { > + handle_watch(watch[XS_WATCH_PATH], watch[XS_WATCH_TOKEN]); > + free(watch); > + } > + > + if ( p[1].revents & POLLIN ) > + handle_event(); > + > + poll(p, 2, 10000); Can you just use an infinite timeout and rely on the signal interrupting the system call? Regards, Jason
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