Bug#850425: mpt3sas "swiotlb buffer is full" problem only under Xen
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.
~Andrew
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