Re: [PATCH v2 2/3] virtio_ring: Support DMA APIs

[Christian Borntraeger]

Am 28.10.2015 um 15:04 schrieb David Woodhouse:
> On Wed, 2015-10-28 at 14:52 +0900, Christian Borntraeger wrote:
>>0059b25a: e3201024   lg  %r2,32(%r1)
>>   #0059b260: e310b0a4   lg  %r1,160(%r11)
>>   >0059b266: 4810100c   lh  %r1,12(%r1)
> 
> Precisely what is that? Is that loading ->archdata.dev_ops (offset 160)
> from a device and then trying to find the ->unmap_page method therein?
> 

qemu 2.4 works, and current qemu master has a broken gdb serverI am going 
to fix
this first.
What I can tell, that the problem goes away if I disable virtio 1.0 so I assume
that things are fine when Andy sends a v4 with the endianess fixes.

Christian

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Re: [PATCH v2 2/3] virtio_ring: Support DMA APIs

[David Woodhouse]

On Wed, 2015-10-28 at 14:52 +0900, Christian Borntraeger wrote:
>0059b25a: e3201024   lg  %r2,32(%r1)
>   #0059b260: e310b0a4   lg  %r1,160(%r11)
>   >0059b266: 4810100c   lh  %r1,12(%r1)

Precisely what is that? Is that loading ->archdata.dev_ops (offset 160)
from a device and then trying to find the ->unmap_page method therein?

-- 
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Re: [PATCH v2 2/3] virtio_ring: Support DMA APIs

[Christian Borntraeger]

Am 28.10.2015 um 14:30 schrieb Andy Lutomirski:

> +static void vring_unmap_one(const struct vring_virtqueue *vq,
> + struct vring_desc *desc)
> +{
> + u16 flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
> +
> + if (flags & VRING_DESC_F_INDIRECT) {
> + dma_unmap_single(vring_dma_dev(vq),
> +  virtio64_to_cpu(vq->vq.vdev, desc->addr),
> +  virtio32_to_cpu(vq->vq.vdev, desc->len),
> +  (flags & VRING_DESC_F_WRITE) ?
> +  DMA_FROM_DEVICE : DMA_TO_DEVICE);
> + } else {
> + dma_unmap_page(vring_dma_dev(vq),
> +virtio64_to_cpu(vq->vq.vdev, desc->addr),
> +virtio32_to_cpu(vq->vq.vdev, desc->len),
> +(flags & VRING_DESC_F_WRITE) ?
> +DMA_FROM_DEVICE : DMA_TO_DEVICE);
> + }
> +}
> +



I still have a failure in this:

[1.913040] Unable to handle kernel pointer dereference in virtual kernel 
address space
[1.913044] failing address: 0c80 TEID: 0c800803
[1.913045] Fault in home space mode while using kernel ASCE.
[1.913048] AS:00d56007 R3:0c7f0007 S:0020 
[1.913099] Oops: 0010 ilc:2 [#1] SMP 
[1.913142] Modules linked in:
[1.913144] CPU: 4 PID: 50 Comm: kworker/u18:1 Not tainted 4.3.0-rc3+ #252
[1.913150] Workqueue: events_unbound call_usermodehelper_exec_work
[1.913152] task: 0bb8b310 ti: 0bba8000 task.ti: 
0bba8000
[1.913154] Krnl PSW : 0404e0018000 0059b266 
(vring_unmap_one+0x46/0x8d0)
[1.913158]R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 
EA:3
Krnl GPRS:  0c80 0c036800 0c80
[1.913161]005a21a8   

[1.913162]0704c0018000 04000bdbfce8 0c082000 
0bdbf6e8
[1.913164]0400  0bdbf988 
0bdbf6e8
[1.913170] Krnl Code: 0059b254: e310b0a80004lg  
%r1,168(%r11)
   0059b25a: e3201024   lg  %r2,32(%r1)
  #0059b260: e310b0a4   lg  %r1,160(%r11)
  >0059b266: 4810100c   lh  %r1,12(%r1)
   0059b26a: e320b2a80024   stg %r2,680(%r11)
   0059b270: 4010b2a6   sth %r1,678(%r11)
   0059b274: e310b2a80004   lg  %r1,680(%r11)
   0059b27a: e310b2980024   stg %r1,664(%r11)
[1.913183] Call Trace:
[1.913185] ([<0059b74c>] vring_unmap_one+0x52c/0x8d0)
[1.913187]  [<005a21a8>] detach_buf+0x720/0x788
[1.913188]  [<005a2830>] virtqueue_get_buf+0x620/0x908
[1.913191]  [<005e5336>] virtblk_done+0xa6/0x120
[1.913192]  [<005a3e46>] vring_interrupt+0x2a6/0x2c0
[1.913224]  [<006c9bdc>] virtio_airq_handler+0x7c/0x120
[1.913226]  [<0065f88c>] do_airq_interrupt+0xa4/0xc8
[1.913229]  [<001b79a0>] handle_irq_event_percpu+0x60/0x1f0
[1.913230]  [<001bbbea>] handle_percpu_irq+0x72/0xa0
[1.913232]  [<001b6fa4>] generic_handle_irq+0x4c/0x78
[1.913234]  [<0010cc7c>] do_IRQ+0x64/0x88
[1.913236]  [<00815d42>] io_int_handler+0x10a/0x218
[1.913238]  [<00104268>] copy_thread+0x78/0x1a0
[1.913240] ([<001548f8>] copy_process.isra.11+0x750/0x1a80)
[1.913242]  [<00156122>] _do_fork+0x9a/0x338
[1.913243]  [<0015644e>] kernel_thread+0x4e/0x60
[1.913245]  [<0016da7a>] call_usermodehelper_exec_work+0x7a/0xf0
[1.913247]  [<00171c06>] process_one_work+0x1b6/0x490
[1.913248]  [<00171f38>] worker_thread+0x58/0x588
[1.913250]  [<001788fa>] kthread+0x10a/0x110
[1.913252]  [<00815a8e>] kernel_thread_starter+0x6/0xc
[1.913254]  [<00815a88>] kernel_thread_starter+0x0/0xc
[1.913255] Last Breaking-Event-Address:
[1.913256]  [<005a21a2>] detach_buf+0x71a/0x788
[1.913258]  
[1.913263] Kernel panic - not syncing: Fatal exception in interrupt

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