From: Jason Wang <jasowang@redhat.com>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
Stefan Hajnoczi <stefanha@redhat.com>,
Laurent Vivier <lvivier@redhat.com>,
linux-kernel@vger.kernel.org, Eli Cohen <elic@nvidia.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Max Gurtovoy <mgurtovoy@nvidia.com>
Subject: Re: [PATCH RFC 00/12] vdpa: generalize vdpa simulator and add block device
Date: Mon, 21 Dec 2020 11:16:54 +0800 [thread overview]
Message-ID: <7dd3ed02-36c3-fcfd-0a1d-9c31af6f473e@redhat.com> (raw)
In-Reply-To: <20201218113816.zcyeyqipux4ao4cp@steredhat>
On 2020/12/18 下午7:38, Stefano Garzarella wrote:
> On Mon, Nov 16, 2020 at 11:37:48AM +0800, Jason Wang wrote:
>>
>> On 2020/11/13 下午9:47, Stefano Garzarella wrote:
>>> Thanks to Max that started this work!
>>> I took his patches, and extended the block simulator a bit.
>>>
>>> This series moves the network device simulator in a new module
>>> (vdpa_sim_net) and leaves the generic functions in the vdpa_sim core
>>> module, allowing the possibility to add new vDPA device simulators.
>>> Then we added a new vdpa_sim_blk module to simulate a block device.
>>>
>>> I'm not sure about patch 11 ("vringh: allow vringh_iov_xfer() to skip
>>> bytes when ptr is NULL"), maybe we can add a new functions instead of
>>> modify vringh_iov_xfer().
>>>
>>> As Max reported, I'm also seeing errors with vdpa_sim_blk related to
>>> iotlb and vringh when there is high load, these are some of the error
>>> messages I can see randomly:
>>>
>>> vringh: Failed to access avail idx at 00000000e8deb2cc
>>> vringh: Failed to read head: idx 6289 address 00000000e1ad1d50
>>> vringh: Failed to get flags at 000000006635d7a3
>>>
>>> virtio_vdpa vdpa0: vringh_iov_push_iotlb() error: -14 offset:
>>> 0x2840000 len: 0x20000
>>> virtio_vdpa vdpa0: vringh_iov_pull_iotlb() error: -14 offset:
>>> 0x58ee000 len: 0x3000
>>>
>>> These errors should all be related to the fact that iotlb_translate()
>>> fails with -EINVAL, so it seems that we miss some mapping.
>>
>>
>> Is this only reproducible when there's multiple co-current accessing
>> of IOTLB? If yes, it's probably a hint that some kind of
>> synchronization is still missed somewhere.
>>
>> It might be useful to log the dma_map/unmp in both virtio_ring and
>> vringh to see who is missing the map.
>>
>
> Just an update about these issues with vdpa-sim-blk.
> I've been focusing a little bit on these failures over the last few
> days and have found two issues related to the IOTLB/IOMMU:
>
> 1. Some requests coming from the block layer fills the SG list with
> multiple buffers that had the same physical address. This happens for
> example while using 'mkfs', at some points multiple sectors are zeroed
> so multiple SG elements point to the same physical page that is zeroed.
> Since we are using vhost_iotlb_del_range() in the
> vdpasim_unmap_page(), this removes all the overlapped ranges. I fixed
> removing a single map in vdpasim_unmap_page(), but has an alternative
> we can implement some kind of reference counts.
I think we need to do what hardware do. So using refcount is probably
not a good ida.
>
> 2. There was a race between dma_map/unmap and the worker thread, since
> both are accessing the IOMMU. Taking the iommu_lock while using
> vhost_iotlb_* API in the worker thread fixes the "vringh: Failed to *"
> issues.
>
> Whit these issues fixed the vdpa-blk simulator seems to work well.
> I'll send the patches next week or after the break.
Good to know this.
Thanks
>
> Thanks,
> Stefano
>
next prev parent reply other threads:[~2020-12-21 3:18 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 13:47 [PATCH RFC 00/12] vdpa: generalize vdpa simulator and add block device Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 01/12] vhost-vdpa: add support for vDPA blk devices Stefano Garzarella
2020-11-17 10:57 ` Stefan Hajnoczi
2020-11-17 15:05 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 02/12] vdpa: split vdpasim to core and net modules Stefano Garzarella
2020-11-16 4:00 ` Jason Wang
2020-11-16 9:39 ` Stefano Garzarella
2020-11-18 13:14 ` Stefano Garzarella
2020-11-19 6:16 ` Jason Wang
2020-11-13 13:47 ` [PATCH RFC 03/12] vdpa_sim: remove hard-coded virtq count Stefano Garzarella
2020-11-16 4:02 ` Jason Wang
2020-11-13 13:47 ` [PATCH RFC 04/12] vdpa: add vdpa simulator for block device Stefano Garzarella
2020-11-16 4:10 ` Jason Wang
2020-11-16 10:17 ` Stefano Garzarella
2020-11-17 11:11 ` Stefan Hajnoczi
2020-11-17 14:16 ` Stefano Garzarella
2020-11-17 16:43 ` Stefan Hajnoczi
2020-11-17 17:38 ` Stefano Garzarella
2020-11-18 11:23 ` Stefan Hajnoczi
2020-11-18 11:39 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 05/12] vdpa_sim: remove the limit of IOTLB entries Stefano Garzarella
2020-11-16 4:12 ` Jason Wang
2020-11-16 10:22 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 06/12] vdpa_sim: add struct vdpasim_device to store device properties Stefano Garzarella
2020-11-16 4:14 ` Jason Wang
2020-11-16 10:30 ` Stefano Garzarella
2020-11-17 11:23 ` Stefan Hajnoczi
2020-11-17 14:24 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 07/12] vdpa_sim: move config management outside of the core Stefano Garzarella
2020-11-16 4:18 ` Jason Wang
2020-11-16 10:42 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 08/12] vdpa_sim: use kvmalloc to allocate vdpasim->buffer Stefano Garzarella
2020-11-16 4:19 ` Jason Wang
2020-11-13 13:47 ` [PATCH RFC 09/12] vdpa_sim: make vdpasim->buffer size configurable Stefano Garzarella
2020-11-16 4:19 ` Jason Wang
2020-11-13 13:47 ` [PATCH RFC 10/12] vdpa_sim: split vdpasim_virtqueue's iov field in riov and wiov Stefano Garzarella
2020-11-16 4:21 ` Jason Wang
2020-11-17 11:27 ` Stefan Hajnoczi
2020-11-20 14:41 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 11/12] vringh: allow vringh_iov_xfer() to skip bytes when ptr is NULL Stefano Garzarella
2020-11-16 4:32 ` Jason Wang
2020-11-16 11:48 ` Stefano Garzarella
2020-11-13 13:47 ` [PATCH RFC 12/12] vdpa_sim_blk: implement ramdisk behaviour Stefano Garzarella
2020-11-16 5:25 ` Jason Wang
2020-11-16 11:08 ` Stefano Garzarella
2020-11-16 9:50 ` Michael S. Tsirkin
2020-11-16 11:23 ` Stefano Garzarella
2020-11-17 11:36 ` Stefan Hajnoczi
2020-11-17 14:32 ` Stefano Garzarella
2020-11-16 3:37 ` [PATCH RFC 00/12] vdpa: generalize vdpa simulator and add block device Jason Wang
2020-11-16 8:53 ` Stefano Garzarella
2020-12-18 11:38 ` Stefano Garzarella
2020-12-21 3:16 ` Jason Wang [this message]
2020-12-21 11:14 ` Stefano Garzarella
2020-12-22 2:44 ` Jason Wang
2020-12-22 10:57 ` Stefano Garzarella
2020-12-22 12:29 ` Jason Wang
2020-12-22 12:56 ` Jason Wang
2020-12-22 13:23 ` Stefano Garzarella
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7dd3ed02-36c3-fcfd-0a1d-9c31af6f473e@redhat.com \
--to=jasowang@redhat.com \
--cc=elic@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lvivier@redhat.com \
--cc=mgurtovoy@nvidia.com \
--cc=mst@redhat.com \
--cc=sgarzare@redhat.com \
--cc=stefanha@redhat.com \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).