From: David Woodhouse Date: Fri, 20 Oct 2023 16:15:27 +0000 (+0100) Subject: hvc/xen: fix event channel handling for secondary consoles X-Git-Tag: block-6.7-2023-11-10~26^2~23 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ef5dd8ec88ac11e8e353164407d55b73c988b369;p=linux-block.git hvc/xen: fix event channel handling for secondary consoles The xencons_connect_backend() function allocates a local interdomain event channel with xenbus_alloc_evtchn(), then calls bind_interdomain_evtchn_to_irq_lateeoi() to bind to that port# on the *remote* domain. That doesn't work very well: (qemu) device_add xen-console,id=con1,chardev=pty0 [ 44.323872] xenconsole console-1: 2 xenbus_dev_probe on device/console/1 [ 44.323995] xenconsole: probe of console-1 failed with error -2 Fix it to use bind_evtchn_to_irq_lateeoi(), which does the right thing by just binding that *local* event channel to an irq. The backend will do the interdomain binding. This didn't affect the primary console because the setup for that is special — the toolstack allocates the guest event channel and the guest discovers it with HVMOP_get_param. Fixes: fe415186b43d ("xen/console: harden hvc_xen against event channel storms") Signed-off-by: David Woodhouse Reviewed-by: Juergen Gross Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-2-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index 98764e740c07..f24e285b6441 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -433,7 +433,7 @@ static int xencons_connect_backend(struct xenbus_device *dev, if (ret) return ret; info->evtchn = evtchn; - irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); + irq = bind_evtchn_to_irq_lateeoi(evtchn); if (irq < 0) return irq; info->irq = irq;