Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #266794

Re: Debian/Xen on ARM: How to identify source of an unhandled SMC call during boot?

Show all headers | View raw

Am 25.01.2024 um 22:28 schrieb Paul Leiber:
> Dear Debian user list members,
> 
> I am trying to run network related stuff (Samba, Zabbix) on a Raspberry 
> Pi 4B in a virtualized environment using Debian Bookworm and Xen. I am 
> running into reproducible complete system crashes/reboots due to a Xen 
> watchdog triggering under certain, seemingly strange conditions (the 
> number of VLANs involved seems to play a role, running tcpdump on 
> certain interfaces prevents this issue, ...). If you are interested in 
> the long version, you can find it here [1].
> 
> Some people on xen-devel pointed out to me two unhandled SMC calls in 
> the boot logs which could be the root of the problem. I am now trying to 
> find out where these calls come from to get closer to the root cause. 
> The suspected calls are the following ones:
> 
> (XEN) d0v0 Unhandled SMC/HVC: 0x84000050
> (XEN) d0v0 Unhandled SMC/HVC: 0x8600ff01
> 
> These calls happen during the Dom0 boot process, so it's something from 
> inside Linux and nothing Xen related, I've been told. The current 
> working hypothesis is that the calls are trying to find some module not 
> emulated by Xen and are therefore failing, leading to Linux waiting for 
> the reply, and subsequently to the Xen watchdog triggering and rebooting.
> 
>  From what I could find out in ARM documentation, the unhandled SMC 
> calls probably have the following purpose:
> 
> 0x84000050 = TRNG_VERSION, returns the implemented TRNG (True Random 
> Number Generator) ABI version [2]
> 0x8600ff01 = Call UID Query for Vendor Specific Hypervisor Service, 
> Returns a unique identifier of the service provider [3]
> 
> The more likely cause is the second call to the address 0x8600ff01.
> 
> Now I simply have no idea how to find out where in the Linux boot 
> process these calls are made. I tried poking into the Linux sources a 
> bit, and I couldn't find an exact match for these call addresses, so I 
> assume these addresses are assembled from different parts. There are 
> some matches for "0x8600" and for "ff01", but I couldn't identify if 
> these matches are relevant.
> 
> I tried to find out if strace could help, but from what I understand, 
> this is related to commands coming from userspace, so I am not sure that 
> strace helps during the boot process.
> 
> I'd appreciate it if somebody more knowledgeable would point me in the 
> right direction. If more information is needed, I can provide it.
> 
> Thanks,
> 
> Paul
> 
> [1] 
> https://lists.xenproject.org/archives/html/xen-devel/2023-10/msg00796.html
> [2] https://developer.arm.com/documentation/den0098/latest/
> [3] 
> https://documentation-service.arm.com/static/628b755ce3c4322a76af56de?token=
> 

Hm, no reply so far. Is this maybe the wrong list? Should I post this 
rather somewhere else?

Paul

Back to linux.debian.user | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Debian/Xen on ARM: How to identify source of an unhandled SMC call  during boot? Paul Leiber <paul@onlineschubla.de> - 2024-01-25 22:50 +0100
  Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? Paul Leiber <paul@onlineschubla.de> - 2024-01-31 08:10 +0100
    Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? "Andrew M.A. Cater" <amacater@einval.com> - 2024-01-31 19:10 +0100
      Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? Paul Leiber <paul@onlineschubla.de> - 2024-01-31 23:10 +0100
    Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? hw <hw@adminart.net> - 2024-01-31 22:10 +0100
      Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? Tixy <tixy@yxit.co.uk> - 2024-01-31 23:20 +0100
        Re: Debian/Xen on ARM: How to identify source of an unhandled SMC  call during boot? Paul Leiber <paul@onlineschubla.de> - 2024-02-17 18:20 +0100

csiph-web