From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: How to display dom0 kernel printk on hvc0 Date: Thu, 07 Aug 2014 15:52:16 +0100 Message-ID: <53E392A0.10705@linaro.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XFP3G-0004tb-VO for xen-devel@lists.xenproject.org; Thu, 07 Aug 2014 14:52:23 +0000 Received: by mail-we0-f173.google.com with SMTP id q58so4373942wes.18 for ; Thu, 07 Aug 2014 07:52:21 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini , manish jaggi Cc: Ian Campbell , Vijay Kilari , manish.jaggi@caviumnetworks.com, Julien Grall , stefano.stabellini@citrix.com, David Vrabel , xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org On 08/07/2014 03:36 PM, Stefano Stabellini wrote: > On Thu, 7 Aug 2014, manish jaggi wrote: >> Thanks, >> I manged to do something similar in the meantime. I am seeing a crash after I do /etc/init.d/xencommns start >> >> [] clear_bit+0x14/0x30 >> [] ack_dynirq+0x44/0x58 >> [] handle_edge_irq+0x74/0x178 >> [] evtchn_fifo_handle_events+0x280/0x288 >> [] __xen_evtchn_do_upcall+0x68/0xd0 >> [] xen_hvm_evtchn_do_upcall+0x8/0x18 >> [] xen_arm_callback+0x4c/0x68 >> [] handle_percpu_devid_irq+0x88/0x120 >> [] generic_handle_irq+0x24/0x40 >> [] handle_IRQ+0x40/0xa8 >> [] gic_handle_irq+0x50/0xa0 >> >> I found that consume_one_event calls handle_irq_for_port which gets IRQ=7 in case of a crash. >> What is the use of IRQ 7 ? >> IRQ1 is UART which i saw in cat /proc/interrupts > > What kernel version are you using? > > It looks like the FIFO event channel is not properly initialized. > You could try switching to the old style 2-level ABI: > > diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c > index 84b4bfb..4a23e08 100644 > --- a/drivers/xen/events/events_fifo.c > +++ b/drivers/xen/events/events_fifo.c > @@ -428,6 +428,8 @@ int __init xen_evtchn_fifo_init(void) > int cpu = get_cpu(); > int ret; > > + return -1; > + > ret = evtchn_fifo_init_control_block(cpu); > if (ret < 0) > goto out; You don't need to recompile the kernel. xen.fifo_events=0 in the command line will choose the 2-level ABI. Regards, -- Julien Grall