[mythtv-users] Xen DomU Backend & Nova-T

Gerald Brandt gbr at majentis.com
Wed Dec 24 00:53:04 UTC 2008


Hi, 

I have 2 DomU's running, both with PVR-150's. One is the Master Backend, and the other is the slave. When the HDPVR becomes stable, I'll have 3 DomU's. 

This is what I had to do on my Dom0 boot grub: 

pciback.permissive pciback.hide=(06:01.0)(06:02.0) dom0_mem=-256M 

Then on my DomU boot, I did: 
extra = '2 console=xvc0 swiotlb=256,force' 
#extra = '2 console=xvc0 iommu=soft swiotlb=512,force' 
#extra = '2 console=xvc0' 

pci=['06:01.0'] 


The important things are the dom0_mem is dom0's grub, and the swiotlb in the DomU's configs. 

I hope that helps. 

Gerald 

ps: if anyone gets pci passthrough working with Xen HVM, I'd be happy to hear about it. 



----- "Alex Pearson" <alex at apics.co.uk> wrote: 
> Hi All, 
> I've done some searching and come up with nothing, so I hope I'm not 
> walking well trodden ground here! 
> 
> I wish to run my mythbackend in a Xen DomU, using pci forwarding. 
> I've two different types of card, but I've only had chance to try one of 
> them (If I pulled both out of my Production system the other half would 
> kill me! ;-)). 
> 
> The card I'm using is a Hauppauge Nova-T PCI (a dvb-t card) 
> lspci on Dom0: 
> 01:08.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video 
> and Audio Decoder (rev 05) 
> 01:08.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and 
> Audio Decoder [MPEG Port] (rev 05) 
> 01:08.4 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and 
> Audio Decoder [IR Port] (rev 05) 
> 
> I've got the card passed to my domU fine (using 'pciback.permissive 
> pciback.hide=(0000:01:08.0)(0000:01:08.2)(0000:01:08.4)' as a kernel 
> option on the Dom0). I can scan for channels without any issues, but as 
> soon as the card tries to actually record anything I get a kernel oops 
> (pasted at the bottom of email). Is this because the card has tried to 
> use DMA to pass the video and can't? Should this even work? The other 
> card I have is a Hauppauge Nova-T 500, which I believe other people have 
> got working (I believe this may be because the card basically a usb hub 
> and tuners, and so wouldn't move data in the same way, but just a guess 
> as I've not tested it yet). 
> 
> lspci on DomU: 
> 00:00.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video 
> and Audio Decoder (rev 05) 
> 00:00.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and 
> Audio Decoder [MPEG Port] (rev 05) 
> 00:00.4 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and 
> Audio Decoder [IR Port] (rev 05) 
> 
> After the garbled chat above, I guess basically I'm asking: 
> 
> Have people got mythbackend running in DomU's successfully? 
> Have you used either Hauppauge Nova-T PCI or Hauppauge Nova-T 500? 
> 
> 
> Thanks in advance to everyone. 
> 
> Alex 
> 
> Oops output: 
> [14285.301630] Fatal DMA error! Please use 'swiotlb=force' 
> [14285.302780] ----------- [cut here ] --------- [please bite here ] 
> --------- 
> [14285.304031] Kernel BUG at 
> arch/x86_64/kernel/../../i386/kernel/pci-dma-xen.c:132 
> [14285.305327] invalid opcode: 0000 [1] SMP 
> [14285.306611] CPU 0 
> [14285.307821] Modules linked in: ipv6 cx88_dvb cx8802 cx8800 
> cx88_vp3054_i2c cx88xx ir_common mt352 i2c_algo_bit 
> d vb_pll or51132 tveeprom 
> video_buf_dvb compat_ioctl32 video_buf btcx_risc nxt200x videodev 
> isl6421 v4l1_compat zl103 53 
> v4l2_common cx24123 lgdt330x cx22702 i2c_core evdev joydev 
> [14285.311737] Pid: 1014, comm: cx88[0] dvb Not tainted 2.6.18.8 #1 
> [14285.313109] RIP: e030:[<ffffffff80211367>] [<ffffffff80211367>] 
> dma_map_sg+0x141/0x1ae 
> [14285.314457] RSP: e02b:ffff88001bfb3e00 EFLAGS: 00010282 
> [14285.315781] RAX: 000000000000003e RBX: ffff88000161ebe0 RCX: 
> 0000000100000000 
> [14285.317103] RDX: ffffffffff5fd000 RSI: 0000000000000001 RDI: 
> ffffffff805322e0 
> [14285.318440] RBP: ffff88001ee0b2c0 R08: ffff880001827508 R09: 
> 000000000000003c 
> [14285.319812] R10: 0000000000001e62 R11: 0000000000001e27 R12: 
> 0000000000000000 
> [14285.321166] R13: 0000000000000006 R14: ffff880001a54070 R15: 
> 6db6db6db6db6db7 
> [14285.322510] FS: 00002b07b8f1d350(0000) GS:ffffffff805b4000(0000) 
> knlGS:0000000000000000 
> [14285.323875] CS: e033 DS: 0000 ES: 0000 
> [14285.325223] Process cx88[0] dvb (pid: 1014, threadinfo 
> ffff88001bfb2000, task ffff880001a1f100) 
> [14285.326645] Stack: 0000000000000002 ffff88001f1f0230 
> ffff88001eefe8e0 ffff880001a54000 
> [14285.328099] ffff88001eefe800 ffff88001eefe8e0 0000000000000002 
> ffffffff8804a1c2 
> [14285.329592] ffff88001f1f0200 ffff88001eefe8e8 0000000000005e00 
> ffffffff880a2f30 
> [14285.329657] Call Trace: 
> [14285.332451] [<ffffffff8804a1c2>] :video_buf:videobuf_dma_map+0x116/0x15a 
> [14285.334086] [<ffffffff880a2f30>] :cx8802:cx8802_buf_prepare+0x9e/0xe6 
> [14285.335944] [<ffffffff88049385>] 
> :video_buf:videobuf_read_start+0xd9/0x167 
> [14285.337587] [<ffffffff880563d2>] 
> :video_buf_dvb:videobuf_dvb_thread+0x0/0x162 
> [14285.339394] [<ffffffff8805641a>] 
> :video_buf_dvb:videobuf_dvb_thread+0x48/0x162 
> [14285.340942] [<ffffffff880563d2>] 
> :video_buf_dvb:videobuf_dvb_thread+0x0/0x162 
> [14285.342413] [<ffffffff8023dfa6>] keventd_create_kthread+0x0/0x62 
> [14285.343885] [<ffffffff8023e0dc>] kthread+0xd4/0x108 
> [14285.345364] [<ffffffff8020aac8>] child_rip+0xa/0x12 
> [14285.346834] [<ffffffff8023dfa6>] keventd_create_kthread+0x0/0x62 
> [14285.348328] [<ffffffff803f7885>] dmx_ts_feed_set+0x0/0x121 
> [14285.349864] [<ffffffff8023e008>] kthread+0x0/0x108 
> [14285.351362] [<ffffffff8020aabe>] child_rip+0x0/0x12 
> [14285.352840] 
> [14285.354268] 
> [14285.354269] Code: 0f 0b 68 2b ac 4d 80 c2 84 00 48 8b 7d 00 48 2b 3d 
> ec e7 40 
> [14285.357142] RIP [<ffffffff80211367>] dma_map_sg+0x141/0x1ae 
> [14285.358551] RSP <ffff88001bfb3e00> 
> [14285.359917] 
> focus:~# 
> 
> xm dmesg: 
> (XEN) Xen version 3.3-unstable (Debian 3.3-unstable+hg17961-1) 
> (waldi at debian.org) (gcc version 4.3.1 (Debian 4.3.1-4) ) Fri Jul 4 
> 18:44:42 UTC 2008 
> 
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