Re: [Qemu-devel] [PATCH] apic: Make APIC ID limit error message clearer

[Markus Armbruster <armbru@redhat.com>]

Eduardo Habkost <ehabkost@redhat.com> writes:

> On Mon, Dec 03, 2018 at 07:07:10PM -0200, Wainer dos Santos Moschetta wrote:
>> 
>> On 11/26/2018 08:56 PM, Eduardo Habkost wrote:
>> > Remove the "apic initialization failed" prefix (it conveys no
>> > useful information), replace "invalid" with "too large", and add
>> > an error hint with two possible solutions for the problem.
>> > 
>> > Before:
>> > 
>> >    $ qemu-system-x86_64 -machine q35 -smp 256
>> >    qemu-system-x86_64: apic initialization failed. APIC ID 255 is invalid
>> > 
>> > After:
>> > 
>> >    $ qemu-system-x86_64 -machine q35 -smp 256 -display none
>> >    qemu-system-x86_64: APIC ID 255 is too large
>> 
>> I would keep the problem "apic initialization failed" sentence. "APIC ID 255
>> is too large" is just the cause.
>
> I'm not sure I agree.  "APIC initialization failed" doesn't
> convey any useful information to the user, does it?

Concur.

>> >    Possible solutions:
>> >    * Lowering the number of VCPUs on the -smp option
>> >    * Using accel=kvm,kernel-irqchip=on or accel=kvm,kernel-irqchip=split
>> > 
>> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>> > ---
>> > I'm not sure this is the best way to provide usage hints to the
>> > user.  Any suggestions?
>> 
>> As a noob, I can testify that this kind of suggestion is very useful
>> although there seems to not have many on QEMU. On the other hand, I
>> understand it can make qemu verbose and so annoy people. Thus, maybe those
>> suggestions could be enabled/disabled via options (e.g. -show-hints)?
>
> I can't imagine who would be annoyed by them.

A few lines of hints are fine.  Longer than that and the error becomes
hard to spot among the hints.