[pve-devel] [PATCH qemu-server 5/5] cpu config: die on hotplug of non x86_64 CPUs

[Filip Schauer]

Here is a fixed patch v2:

https://lists.proxmox.com/pipermail/pve-devel/2024-March/062153.html

On 08/03/2024 14:53, Fiona Ebner wrote:
> Am 08.03.24 um 14:34 schrieb Thomas Lamprecht:
>> Am 21/02/2024 um 15:33 schrieb Filip Schauer:
>>> When attempting a CPU hotplug on an architecture other than x86_64, die
>>> with a clean error instead of attempting a hotplug with a known
>>> non-working device command line. Also move the corresponding FIXME up to
>>> the error.
>>>
>>> Signed-off-by: Filip Schauer <f.schauer at proxmox.com>
>>> ---
>>>   PVE/QemuServer/CPUConfig.pm | 4 +++-
>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/PVE/QemuServer/CPUConfig.pm b/PVE/QemuServer/CPUConfig.pm
>>> index 7d471f4..01e4515 100644
>>> --- a/PVE/QemuServer/CPUConfig.pm
>>> +++ b/PVE/QemuServer/CPUConfig.pm
>>> @@ -417,6 +417,9 @@ sub get_custom_model {
>>>   sub print_cpu_device {
>>>       my ($conf, $arch, $id) = @_;
>>>   
>>> +    # FIXME: hot plugging other architectures like our unofficial arch64 support?
>>> +    die "Hotplug of non x86_64 CPU not yet supported" if $arch != 'x86_64';
>> arbitrary strings need to be compared using `eq` and `ne`, as `==` and `!=` can
>> only be used for numerics or strings that can be interpreted to one, so this never
>> could work.
>>
>> Interestingly the if never triggers in the `!=` case but always triggers in the
>> `==` case.
>>
> Because strings that cannot be parsed as a number are interpreted as 0,
> so both (invalid) sides will be 0. Description of parsing rules (from
> [0], wasn't able to find in official docs):
>
>> It follows these basic rules:
>>
>>      Ignore leading whitespace. This is handy when you extract a field out of columnar data and the number doesn't take up the entire column.
>>      Allow for a single leading sign (+ or -)
>>      Skip leading zeros (so, no octal)
>>      Capture decimal ASCII digits (0,1,2,3,4,5,6,7,8,9), allowing for a single decimal point (so, no semantic versioning numbers)
>>      Stop at the first non-decimal-digit character
>>      Whatever you have so far is the number. If you have nothing, the number is 0.
>
> [0]:
> https://stackoverflow.com/questions/70482447/why-is-00-equal-to-0-in-perl/70496787#70496787