Hello,
On 02.10.24 10:17, Ahmad Fatoum wrote:
> I am building for MACHINE = "qemuarm64" already, but something else catches
> my eye: QEMU_USE_KVM = 'True'
>
> I wasn't aware that I need to manually set this. I do this now and it fails
> for other reasons: qemu-system-aarch64: KVM does not support GICv3 emulation
>
> I'll look into how to resolve this and maybe I am lucky and can reproduce
> this issue, once KVM is enabled.
Good news: I managed to reproduce this issue and write a few lines long
reproducer
that I sent in a bug report to the KVM/QEMU development mailing lists:
https://lore.kernel.org/all/[email protected]/
I will look after any fixes that may result.
As far as this series here is concerned, both barebox and U-Boot function
correctly
with KVM disabled, so could we just disable KVM for only the U-Boot/barebox
runqemu tests
to unblock merge of this series?
Some more info on my debugging below.
I managed to reproduce by enabling KVM and changing:
-QB_CPU_KVM = "-cpu host -machine gic-version=3"
+QB_CPU_KVM = "-cpu host -machine virt"
and by disabling migration across the big-little cluster with
taskset -a --cpu-list 2-5
I even got a U-Boot crash register dump:
Flash: 64 MiB
Loading Environment from Flash... *** Warning - bad CRC, using default
environment
In: serial,usbkbd
Out: serial,vidconsole
Err: serial,vidconsole
Bus xhci_pci: Register 8001040 NbrPorts 8
Starting the controller
"Synchronous Abort" handler, esr 0x96000010, far 0x10090040
elr: 0000000000055114 lr : 00000000000550f8 (reloc)
elr: 000000004f724114 lr : 000000004f7240f8
x0 : 0000000010090040 x1 : 0000000000000001
x2 : 0000000000000000 x3 : 0000000000003e80
x4 : 0000000000000038 x5 : 000000004e58e7a2
x6 : 0000000000000000 x7 : 0000000000000000
x8 : 000000004e58ec30 x9 : 00000000ffffffd8
x10: 000000000000000d x11: 0000000000000006
x12: 000000004e58ea88 x13: 000000004e58ed90
x14: 0000000000000000 x15: 000000004e58e7a2
x16: 000000004f716d84 x17: 0000000000000000
x18: 000000004e68ed90 x19: 000000004e695b00
x20: 0000000000000000 x21: 0000000010090040
x22: 0000000010090000 x23: 000000004f79553c
x24: 0000000000000000 x25: 0000000000000000
Removing -enable-kvm makes the issue disappear. barebox also reaches
the shell normally when -enable-kvm is omitted.
Given that I am more familiar with barebox (and the stack traces there
actually walk the stack and contain symbols if the data abort happens
after the vector table is installed), I debugged the issue there and
narrowed it down to a specific encoding of the LDR instruction operating
on an MMIO peripheral.
More information about that in the bug report linked above.
Cheers,
Ahmad
>
> Can you share what SoC is used for the ARM CI server? I assume it doesn't
> run into this problem, because it has a GIC >= v3. Mine is a GIC-400,
> which apparently only implements GICv2.
>
> Cheers,
> Ahmad
>
>>
>> Cheers,
>>
>> Richard
>>
>>
>>
>
>
--
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