Bug#850425: mpt3sas "swiotlb buffer is full" problem only under Xen
On 10/03/2019 23:03, Andrew Cooper wrote:
> On 10/03/2019 21:35, Hans van Kranenburg wrote:
>> found -1 4.19.20-1
>> thanks
>>
>> Hi,
>>
>> Reviving a thing from Jan 2017 here. I don't have this thread in my
>> mailbox, so no inline quotes.
>>
>> I just installed some HP z820 workstation and rebooted it into Xen
>> 4.11.1+26-g87f51bf366-3 with linux 4.19.20-1 as dom0 kernel.
>>
>> During boot I'm greeted by a long list of...
>>
>> [ 14.518793] mpt3sas 0000:02:00.0: swiotlb buffer is full (sz: 65536
>> bytes)
>> [ 14.518899] mpt3sas 0000:02:00.0: swiotlb buffer is full
>> [ 14.518956] mpt3sas 0000:02:00.0: swiotlb buffer is full (sz: 65536
>> bytes)
>> [ 14.518988] sd 6:0:3:0: pci_map_sg failed: request for 786432 bytes!
>> [ 14.519081] mpt3sas 0000:02:00.0: swiotlb buffer is full
>> [ 14.519309] sd 6:0:1:0: pci_map_sg failed: request for 1310720 bytes!
>> [ 14.524611] mpt3sas 0000:02:00.0: swiotlb buffer is full (sz: 65536
>> bytes)
>> [ 14.527309] mpt3sas 0000:02:00.0: swiotlb buffer is full
>> [ 14.527405] sd 6:0:3:0: pci_map_sg failed: request for 786432 bytes!
>> [...]
>>
>> ...and some hangs here and there. This indeed did not happen when
>> booting just Linux, without Xen.
>>
>> Some searching brought me to this Debian bug. So, thanks for writing
>> down all kinds of research here already. Even if it's not fixed upstream
>> yet, this helps a lot. :-)
>>
>> Using dom0_mem=2GiB,max:4GiB instead of dom0_mem=2GiB,max:2GiB (which I
>> started with) makes the errors go away, so workaround confirmed.
>>
>> I can try any of the linked patches, but I see that in message 54,
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=850425#54
>> Andrew says: "IIRC, they were essentially rejected,". Next message, Ian
>> asks "Do you have a reference ?", but I don't see any fup on that.
>>
>> I think I'm fine with this workaround.
>>
>> If someone will ever work on the upstream patches, then this is just to
>> let know that I might be able to help testing. However, I only have one
>> of this type of box and it's gonna be installed as server at some
>> non-profit organization without OOB access, replacing even older donated
>> hardware, so, it will be kinda limited... :)
>
> I think
> https://lists.xen.org/archives/html/xen-devel/2014-12/msg00699.html is
> the last attempt David made to upstream the fixes.
>
> Linux is still broken, and these fixes are still necessary.
>
> Boris/Juergen: Any chance you could look into these patches? I have no
> idea what they they're in against master, but its also liable its now
> more complicated with the host max mfn calculations which have gone in
> more recently.
I'm not sure. Patch 3 of this series is basically already there (see
commit c6d4381220a0087ce19dbf6984d92c451bd6b364). So maybe all we need
is patch 4, which should really be easy to do?
Hans, could you give it a try? You'd need to use a 4.20 kernel at least.
I can do the official patch posting in case you confirm it working.
Adding Konrad as the swiotlb-xen maintainer.
Juergen
Reply to: