[Pkg-xen-devel] Bug#963607: Bug#963607: xen-hypervisor-4.11-amd64: Xen Hypervisor kernel fails to load arcmsr module with "arcmsr0: dma_alloc_coherent got error" message.

[Hans van Kranenburg]

Hi Alex,

On 6/24/20 12:31 PM, Alex Sanderson wrote:
> Package: xen-hypervisor-4.11-amd64
> Version: 4.11.3+24-g14b62ab3e5-1~deb10u1
> Severity: important
> 
> Dear Maintainer,
> 
> After updating to Buster and Xen 4.11 our machine no longer boots the Xen kernel.  The default kernel 4.19.118-2+deb10u1 boots normally.

When booting with Xen, the computer first starts the Xen hypervisor
code. This is the part where you see all the lines with (XEN) at the
beginning appear.

Afterwards, it starts the same 4.19.118-2+deb10u1 Linux kernel that is
used when running without Xen, but it's started as the first virtual
machine, that has extra privileges to access all hardware.

So, Linux vs. Xen + Linux.

> The machine has an Areca 1882IX-16 card in it when the arcmsr module
> tries to load the following error appears. 
> 
> 	Areca RAID Controller0: Model ARC-1882, F/W V1.56 2019-07-30
> 	arcmsr0: dma_alloc_coherent got error
> 
> No drives are discovered and the initramfs prompt is shown.

Ok, so booting the Xen part succeeded, but apparently, when starting the
Linux kernel inside, there's apparently a problem with accessing the
raid controller hardware. Interesting.

This likely means it's not a problem in the Debian packaging part, it's
a problem somewhere in the upstream Xen or Linux code. That means that I
cannot solve this for you, but I can help with tips to gather the right
information, and help finding out what the best place is where we can
report the issue.

> The machine:
>  * Supermicro X9DRW 
>  * Dual Intel(R) Xeon(R) CPU E5-2630L v2 @ 2.40GHz
>  * 128G RAM
>  * Areca ARC-1882IX-16 (1G onboard cache)
> 
> Nothing I have tried is effective:
>  * Turning on BIOS above 4G decoding stops the Intel 10GBE ixgbe driver from functioning and doesn't fix the arcmsr
>  * Unloading and reloading the arcmsr module from initramfs prompt
>  * Downgrading the Areca 1882 bios to v1.52 as per http://faq.areca.com.tw/index.php?action=artikel&cat=7&id=902&artlang=en
>  * Kernel parameters
>  ** pci=nocrs 
>  ** dom0_mem=8G 
>  ** mem=3072M
>  ** mem2048M cma=1024M
>  ** cma=2048
>  ** cma=3076 at 512M
>  ** iommu=1 intel_iommu=1 
>  ** arcmsr.host_can_queue=64 as per http://faq.areca.com.tw/index.php?action=artikel&cat=15&id=387&artlang=en
> 
> I expected the arcmsr module to load and detect disks as it does with
> the stock kernel.
> 
> I can provide sysctl and dmesg output if it helps.

Yes. The first thing needed is full startup logs, and for the Xen part
preferably extra logging. In /etc/default/grub.d/xen.cfg in the
GRUB_CMDLINE_XEN_DEFAULT setting, you can add loglvl=all, and then run
update-grub and try to boot Xen+Linux again.

Do you have a way to capture the logging during boot? Like, a working
serial console or something similar?

The output of dmesg when starting Linux without Xen is of course also
interesting, so we can compare both scenarios.

Hans