Re: [Xen-users] PCI Passthrough without VT-d

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Mar 08, 2010 at 11:23:44AM -0300, Sergio Charpinel Jr. wrote:
>    Thanks Pasi,
>    Tried with Xen from CentOS 5.4 repo, and got the same error.
>    Also with extra = 'swiotlb=force' in DomU conf file.
>    DomU boots, but when I start zoneminder (a software that access the
>    webcam), the kernel panic occurs.
>    I will test another application.
> 

Is the PCI device you passthrough using a shared interrupt (IRQ)? 
If yes, that can (and will) cause problems.

-- Pasi

>    2010/3/5 Pasi Kärkkäinen <[1]pasik@xxxxxx>
> 
>      On Fri, Mar 05, 2010 at 02:01:28PM -0300, Sergio Charpinel Jr. wrote:
>      >    Hi,
>      >    I created a PV guest, and did a passthrough on my PCI USB
>      Controller, to
>      >    use the webcam.
>      >    But, I'm receiving a kernel panic message on my domU afte boot.
>      >    I'm using CentOS 5.4 and Xen 3.4.2
>      >    Password: Fatal DMA error! Please use 'swiotlb=force'
> 
>      Did you try that 'swiotlb=force' option for the guest kernel?
>      Also, does the same problem happen if you run the official EL5 Xen
>      (3.1.2)
>      instead of 3.4.2 ?
> 
>      -- Pasi
>      >    ----------- [cut here ] --------- [please bite here ] ---------
>      >    Kernel BUG at
>      arch/x86_64/kernel/../../i386/kernel/pci-dma-xen.c:394
>      >    invalid opcode: 0000 [1] SMPÂ
>      >    last sysfs file:
>      >
>       
> /devices/xen/pci-0/pci0000:00/0000:00:00.3/usb1/1-1/1-1:1.0/usbdev1.2_ep82/dev
>      >    CPU 0Â
>      >    Modules linked in: autofs4 hidp rfcomm l2cap bluetooth lockd sunrpc
>      >    ip_conntrack_netbios_ns ipt_MASQUERADE xt_mark iptable_nat ip_nat
>      xt_MARK
>      >    iptable_mangle ipt_REJECT xt_state ip_conntrack nfnetlink
>      iptable_filter
>      >    ip_tables ip6t_REJECT xt_tcpudp ip6table_filter ip6_tables x_tables
>      ipv6
>      >    xfrm_nalgo crypto_api dm_mirror dm_multipath scsi_dh scsi_mod
>      parport_pc
>      >    lp parport stv680 compat_ioctl32 videodev v4l1_compat pcspkr
>      v4l2_common
>      >    xennet dm_raid45 dm_message dm_region_hash dm_log dm_mod
>      dm_mem_cache
>      >    xenblk ext3 jbd uhci_hcd ohci_hcd ehci_hcd
>      >    Pid: 1752, comm: zmc Not tainted 2.6.18-164.11.1.el5xen #1
>      >    RIP: e030:[<ffffffff8027217b>] Â [<ffffffff8027217b>]
>      >    dma_map_single+0x12d/0x17d
>      >    RSP: e02b:ffff88000cfb1c78 Â EFLAGS: 00010282
>      >    RAX: 000000000000002f RBX: ffff88000e860000 RCX: ffffffff804f3ba8
>      >    RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
>      >    RBP: 0000000035032000 R08: ffffffff804f3ba8 R09: 0000000000000000
>      >    R10: 000000000000002d R11: ffff88001f4230c0 R12: 0000000000019610
>      >    R13: ffff88001fdef870 R14: ffff88001fb5f980 R15: ffff880010296ad4
>      >    FS: Â 00002b8745423c10(0000) GS:ffffffff805ca000(0000)
>      >    knlGS:0000000000000000
>      >    CS: Â e033 DS: 0000 ES: 0000
>      >    Process zmc (pid: 1752, threadinfo ffff88000cfb0000, task
>      >    ffff88000f4530c0)
>      >    Stack: Â ffff88000f4530c0 Â ffff880010296ac0 Â 00000000ffffffff
>      >    Â ffff880010296ac0Â
>      >    Â ffff88001ff7d400 Â ffffffff803e4200 Â 0000000000000000
>      >    Â 000000d0802572b0Â
>      >     fffffffffff7ffff  ffffffff802c2e18Â
>      >    Call Trace:
>      >    Â [<ffffffff803e4200>] hcd_submit_urb+0x693/0x748
>      >    Â [<ffffffff802c2e18>] mod_zone_page_state+0x27/0x3d
>      >    Â [<ffffffff8020b242>] kmem_cache_alloc+0x62/0x6d
>      >    Â [<ffffffff8025e6e3>] cache_alloc_refill+0x13c/0x4e5
>      >    Â [<ffffffff802cfc34>] __kmalloc+0x8f/0x9f
>      >    Â [<ffffffff881377e0>] :stv680:stv680_start_stream+0x18b/0x1c5
>      >    Â [<ffffffff881397a0>] :stv680:stv680_do_ioctl+0x4e1/0x57b
>      >    Â [<ffffffff8811ddda>] :videodev:video_usercopy+0x1a1/0x265
>      >    Â [<ffffffff881392bf>] :stv680:stv680_do_ioctl+0x0/0x57b
>      >    Â [<ffffffff8031a360>] inode_has_perm+0x56/0x63
>      >    Â [<ffffffff80222789>] __up_read+0x19/0x7f
>      >    Â [<ffffffff802676cd>] do_page_fault+0xfae/0x12e0
>      >    Â [<ffffffff8026ef47>] monotonic_clock+0x35/0x7b
>      >    Â [<ffffffff80243f5c>] do_ioctl+0x55/0x6b
>      >    Â [<ffffffff802316b5>] vfs_ioctl+0x457/0x4b9
>      >    Â [<ffffffff8024e68e>] sys_ioctl+0x59/0x78
>      >    Â [<ffffffff802602f9>] tracesys+0xab/0xb6
>      >    Code: 0f 0b 68 3a 2b 49 80 c2 8a 01 4d 85 ed 74 11 49 8b 85 18 02Â
>      >    RIP Â [<ffffffff8027217b>] dma_map_single+0x12d/0x17d
>      >    Â RSP <ffff88000cfb1c78>
>      >    Â <0>Kernel panic - not syncing: Fatal exception
>      >    2010/3/2 Jan Ä*eÅ¡Ä*ut <[1][2]Jan.Cescut@xxxxxx>
>      >
>      >      Thanks for thorough explanation.
>      >
>      >      Have a nice day,
>      >      Jan
>      >      -----Original Message-----
>      >      From: Pasi KÃ*rkkÃ*inen [mailto:[2][3]pasik@xxxxxx]
>      >      Sent: 27. februar 2010 14:04
>      >      To: Jan Ä*eÅ¡Ä*ut
>      >      Cc: [3][4]xen-users@xxxxxxxxxxxxxxxxxxx
>      >      Subject: Re: [Xen-users] PCI Passthrough without VT-d
>      >
>      >      On Fri, Feb 26, 2010 at 11:29:22PM +0100, Jan ?eš?ut wrote:
>      >      > Â  Â As I read XEN supports assigning a pci device to an
>      unprivileged
>      >      domain
>      >      > Â  Â without hardware supporting it. Has anyone already tried
>      it? Are
>      >      there any
>      >      > Â  Â security risks? If I understand correctly how PCI
>      passthrough
>      >      works the
>      >      > Â  Â performance should be the same as using the pci device in
>      native
>      >      mode. Is
>      >      > Â  Â it so? I have a PCI video card which would like to use
>      inside a
>      >      VM running
>      >      > Â  Â Windows XP.
>      >      >
>      >
>      >      Xen supports PCI passthrough to _PV_ (paravirtual) guests without
>      VT-d,
>      >      and has actually supported that for years. There are some
>      potential
>      >      security
>      >      risks in this, since the PV guest gets full DMA control of the
>      PCI
>      >      device
>      >      and could use it for malicious purposes.
>      >
>      >      Xen PCI passthrough to HVM guests (=Windows) requires VT-d
>      hardware
>      >      support.
>      >
>      >      Also, PCI passthrough of a VGA/video card is not as simple as PCI
>      >      passthrough
>      >      of other cards (nic, disk controller, usb controller).
>      >
>      >      VGA has lots of legacy stuff related to it, some memory ranges,
>      IO
>      >      ports, VGA BIOS,
>      >      etc that have to be 'passed through' aswell, and emulated.
>      >
>      >      Xen 4.0.0 will have PCI passthrough support of primary VGA
>      adapters, but
>      >      it requires
>      >      VT-d support as stated already earlier.
>      >
>      >      -- Pasi
>      >
>      >      ps. There is actually a hack/patch available that allows PCI
>      passthrough
>      >      to HVM guest
>      >      without VT-d, but that only works for the _first_ started HVM
>      guest, and
>      >      it's experimental
>      >      and not supported in any way. iirc the patch is available in
>      xen-devel
>      >      archives.
>      >
>      >      _______________________________________________
>      >      Xen-users mailing list
>      >      [4][5]Xen-users@xxxxxxxxxxxxxxxxxxx
>      >      [5][6]http://lists.xensource.com/xen-users
>      >
>      >    --
>      >    Sergio Roberto Charpinel Jr.
>      >


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