Re: [Xen-users] Odd domU Reboot Bug (possibly VGA passthrough related)

[Gordan Bobic <gordan@xxxxxxxxxx>]

On 07/01/2013 07:22 PM, Gordan Bobic wrote:
> Diet version:
>
> faux-Quadro 6000 VGA passthrough, works lovely when first started.
> Starting it using this script:
>
> modprobe xen-pciback
>
> # USB Controllers
> xl pci-assignable-add 0000:00:1a.0
> xl pci-assignable-add 0000:00:1d.2
>
>
> # Audio
> xl pci-assignable-add 0000:0d:00.0
>
> # NIC
> xl pci-assignable-add 0000:02:00.0
>
> # GPU
> xl pci-assignable-add 0000:0b:00.0
> xl pci-assignable-add 0000:0b:00.1
>
> xl create /etc/xen/edi
>
> vinagre :0
>
>
> But - shut down the domU (XP x64). Start it up again, and:
>
> Jun 30 18:59:08 normandy kernel: irq 18: nobody cared (try booting with
> the "irqpoll" option)
> Jun 30 18:59:08 normandy kernel: Pid: 0, comm: swapper/0 Tainted: PF
>        O 3.9.5-1.el6xen.x86_64 #1
> Jun 30 18:59:08 normandy kernel: Call Trace:
> Jun 30 18:59:08 normandy kernel: NVRM: VM: nv_alloc_contig_pages: failed
> to DMA-map memory
> Jun 30 18:59:08 normandy kernel: <IRQ>  [<ffffffff810d416d>]
> __report_bad_irq+0x3d/0xe0
> Jun 30 18:59:08 normandy kernel: [<ffffffff810d4366>]
> note_interrupt+0x156/0x210
> Jun 30 18:59:08 normandy kernel: [<ffffffff810d1b99>]
> handle_irq_event_percpu+0xc9/0x210
> Jun 30 18:59:08 normandy kernel: [<ffffffff810d1d21>]
> handle_irq_event+0x41/0x70
> Jun 30 18:59:08 normandy kernel: [<ffffffff810d4a99>]
> handle_fasteoi_irq+0x59/0xf0
> Jun 30 18:59:08 normandy kernel: [<ffffffff81302780>]
> __xen_evtchn_do_upcall+0x240/0x380
> Jun 30 18:59:08 normandy kernel: [<ffffffff813028ff>]
> xen_evtchn_do_upcall+0x2f/0x50
> Jun 30 18:59:08 normandy kernel: [<ffffffff8155c57e>]
> xen_do_hypervisor_callback+0x1e/0x30
> Jun 30 18:59:08 normandy kernel: <EOI>  [<ffffffff810013aa>] ?
> xen_hypercall_sched_op+0xa/0x20
> Jun 30 18:59:08 normandy kernel: [<ffffffff810013aa>] ?
> xen_hypercall_sched_op+0xa/0x20
> Jun 30 18:59:08 normandy kernel: [<ffffffff8100a2a0>] ?
> xen_safe_halt+0x10/0x20
> Jun 30 18:59:08 normandy kernel: [<ffffffff8101d166>] ?
> default_idle+0x46/0x100
> Jun 30 18:59:08 normandy kernel: [<ffffffff8101ca99>] ? cpu_idle+0xd9/0x120
> Jun 30 18:59:08 normandy kernel: [<ffffffff8153a0d5>] ? rest_init+0x75/0x80
> Jun 30 18:59:08 normandy kernel: [<ffffffff81801200>] ?
> start_kernel+0x40e/0x41b
> Jun 30 18:59:08 normandy kernel: [<ffffffff81800c10>] ?
> repair_env_string+0x5b/0x5b
> Jun 30 18:59:08 normandy kernel: [<ffffffff818005f1>] ?
> x86_64_start_reservations+0x2a/0x2c
> Jun 30 18:59:08 normandy kernel: [<ffffffff818045ae>] ?
> xen_start_kernel+0x56e/0x570
> Jun 30 18:59:08 normandy kernel: handlers:
> Jun 30 18:59:08 normandy kernel: [<ffffffff813ca4c0>] usb_hcd_irq
> Jun 30 18:59:08 normandy kernel: [<ffffffffa02c3820>] i801_isr [i2c_i801]
> Jun 30 18:59:08 normandy kernel: Disabling IRQ #18
>
> This happens reasonably consistently. The domU comes up only in VGA
> 16-colour mode on VNC.
>
> But - I've found that shutting it down, doing:
> xl mem-set 0 48G
> (the machine has 48GB of RAM) makes it work fine again.
>
> IRQ18 is used by two USB controllers (of which one I'm PCI
> passthrough-ing) and a SMBus (i2c_i801) controller.
>
> The thing that bothers me is that NVRM seems to be what's complaining,
> but the GPU being passed through is firmly under control of xen-pciback.
>
> I don't suppose anyone might have an idea on how to gain some useful
> debug info for a bug report out of this?
Additional - after a while this stops helping - and every time the VM is 
restarted, the dom0 memory drops by a further 2GB, i.e.
Initial: dom0: 48GB
start domU: 46GB/2GB
xl mem-set 0 48GB: dom0:48GB
start domU, crash: 44GB/2GB
xl mem-set 0 48GB: dom0:48GB
start domU, crash: 42GB/2GB

I could have sworn this wasn't happening before. I'll try to work out of 
a recent XSA patch broke something again.
Gordan

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