The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x ef5dd8ec88ac11e8e353164407d55b73c988b369 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023112210-salt-repossess-a9d7@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
ef5dd8ec88ac ("hvc/xen: fix event channel handling for secondary consoles") fe415186b43d ("xen/console: harden hvc_xen against event channel storms") 3bd5371a4da6 ("xen/events: Remove unused bind_evtchn_to_irq_lateeoi()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ef5dd8ec88ac11e8e353164407d55b73c988b369 Mon Sep 17 00:00:00 2001 From: David Woodhouse dwmw@amazon.co.uk Date: Fri, 20 Oct 2023 17:15:27 +0100 Subject: [PATCH] hvc/xen: fix event channel handling for secondary consoles MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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 dwmw@amazon.co.uk Reviewed-by: Juergen Gross jgross@suse.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-2-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
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;