Re: [PATCH v2] x86/shutdown: change default reboot method preference

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Feb 13, 2026 at 01:39:56AM +0100, Marek Marczykowski-Górecki wrote:
> On Fri, Sep 15, 2023 at 09:43:47AM +0200, Roger Pau Monne wrote:
> > The current logic to chose the preferred reboot method is based on the mode 
> > Xen
> > has been booted into, so if the box is booted from UEFI, the preferred 
> > reboot
> > method will be to use the ResetSystem() run time service call.
> > 
> > However, that method seems to be widely untested, and quite often leads to a
> > result similar to:
> > 
> > Hardware Dom0 shutdown: rebooting machine
> > ----[ Xen-4.18-unstable  x86_64  debug=y  Tainted:   C    ]----
> > CPU:    0
> > RIP:    e008:[<0000000000000017>] 0000000000000017
> > RFLAGS: 0000000000010202   CONTEXT: hypervisor
> > [...]
> > Xen call trace:
> >    [<0000000000000017>] R 0000000000000017
> >    [<ffff83207eff7b50>] S ffff83207eff7b50
> >    [<ffff82d0403525aa>] F machine_restart+0x1da/0x261
> >    [<ffff82d04035263c>] F apic_wait_icr_idle+0/0x37
> >    [<ffff82d040233689>] F smp_call_function_interrupt+0xc7/0xcb
> >    [<ffff82d040352f05>] F call_function_interrupt+0x20/0x34
> >    [<ffff82d04033b0d5>] F do_IRQ+0x150/0x6f3
> >    [<ffff82d0402018c2>] F common_interrupt+0x132/0x140
> >    [<ffff82d040283d33>] F 
> > arch/x86/acpi/cpu_idle.c#acpi_idle_do_entry+0x113/0x129
> >    [<ffff82d04028436c>] F 
> > arch/x86/acpi/cpu_idle.c#acpi_processor_idle+0x3eb/0x5f7
> >    [<ffff82d04032a549>] F arch/x86/domain.c#idle_loop+0xec/0xee
> > 
> > ****************************************
> > Panic on CPU 0:
> > FATAL TRAP: vector = 6 (invalid opcode)
> > ****************************************
> > 
> > Which in most cases does lead to a reboot, however that's unreliable.
> 
> It's not relevant anymore, but posting just for the posterity: I
> just found yet another system where EFI ResetSystem() crashes. What's
> interesting about it, it's rather new system - NUC 14 with Lunar Lake.
> It crashes as follows:

Interesting, all the NUC systems I owned had what seemed like proper
UEFI implementations.  However those are the Intel ones.  Lunar Lake
is made by ASUS.

Thanks, Roger.