On 05/02/2024 10:39, Jan Beulich wrote:
>
>
> On 03.02.2024 12:43, Carlo Nonato wrote:
>> On Thu, Feb 1, 2024 at 3:19 PM Jan Beulich <[email protected]> wrote:
>>> On 29.01.2024 18:18, Carlo Nonato wrote:
>>>> @@ -950,6 +951,11 @@ void __init create_domUs(void)
>>>> #endif
>>>> }
>>>>
>>>> + dt_property_read_string(node, "llc-colors", &llc_colors_str);
>>>> + if ( !llc_coloring_enabled && llc_colors_str)
>>>> + printk(XENLOG_WARNING
>>>> + "'llc-colors' found, but LLC coloring is disabled\n");
>>>
>>> Why's this just a warning, when ...
>>
>> This informs the user that this configuration will be ignored, but the DomU
>> can
>> be constructed anyway...
>
> Yet that's a violation of the principle that Julien had outlined when
> discussing whether to panic() in such cases. The property indicates to
> me that the domain ought to be run with coloring enabled, i.e. not much
> different from ...
>
>>>> @@ -960,6 +966,11 @@ void __init create_domUs(void)
>>>> panic("Error creating domain %s (rc = %ld)\n",
>>>> dt_node_name(node), PTR_ERR(d));
>>>>
>>>> + if ( llc_coloring_enabled &&
>>>> + (rc = domain_set_llc_colors_from_str(d, llc_colors_str)) )
>>>> + panic("Error initializing LLC coloring for domain %s (rc =
>>>> %d)\n",
>>>> + dt_node_name(node), rc);
>>>
>>> ... this results in panic()?
>>
>> ... while here we can't continue because there's some error in the
>> configuration and the DomU can't be constructed. Domains must have a valid
>> coloring configuration.
>
> ... the request not being possible to fulfill here.
+1
If the user requests a certain functionality which cannot be fulfilled, we
shall panic.
Take a look at e.g. sve, static-shmem, vpl011.
~Michal
