Re: [PATCH 1/7] backends/hostmem: Drop redundant validation of property "size"

[Markus Armbruster <armbru@redhat.com>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Thu, Nov 12, 2026 at 08:44:28AM +0100, Markus Armbruster wrote:
>> Daniel P. Berrangé <berrange@redhat.com> writes:

[...]

>> > as a separate patch I might suggest

[...]

>> > so that we get the nicer message:
>> >
>> >     $ ./build/qemu-system-x86_64 -object memory-backend-ram,size=0,id=foo
>> >     qemu-system-x86_64: cannot create 'memory-backend-ram' with a size of 0
>> 
>> Your message assumes that the property is only ever set on behalf of an
>> object creation request.  Not true in general, qom-set exists.  I
>> believe it's true here due to the host_memory_backend_mr_inited() guard.
>> But that's not entirely obvious, isn't it?
>> 
>> Possible phrasings that don't assume this:
>> 
>>    property 'size' of 'memory-backend-ram' cannot be zero
>>    cannot set property 'size' of 'memory-backend-ram' to zero
>> 
>> Is one of them good enough?  I doubt this error is common.
>
> I'm fine with either of those, perhaps mildly leaning towards
> the second.
>
>> There are enough "doesn't take value" error messages elsewhere to
>> justify a small series of its own.

Just posted:

    From: Markus Armbruster <armbru@redhat.com>
    Subject: [PATCH] error: Improve a few error messages on setting property to zero
    Date: Thu, 12 Nov 2026 12:47:02 +0100
    Message-ID: <20261112114702.969681-1-armbru@redhat.com>