Re: [PATCH] xen/arm: Print memory size in decimal in construct_domU

[Michal Orzel <michal.orzel@xxxxxxx>]

Hi Julien,

On 03/01/2023 10:56, Julien Grall wrote:
> 
> 
> Hi Michal,
> 
> On 03/01/2023 09:39, Michal Orzel wrote:
>> On 03/01/2023 10:21, Ayan Kumar Halder wrote:
>>>
>>>
>>> Hi Michal,
>>>
>>> On 02/01/2023 14:49, Michal Orzel wrote:
>>>> Printing domain's memory size in hex without even prepending it
>>>> with 0x is not very useful and can be misleading. Switch to decimal
>>>> notation.
>>>>
>>>> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
>>>> ---
>>>>    xen/arch/arm/domain_build.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>>>> index 829cea8de84f..7e204372368c 100644
>>>> --- a/xen/arch/arm/domain_build.c
>>>> +++ b/xen/arch/arm/domain_build.c
>>>> @@ -3774,7 +3774,7 @@ static int __init construct_domU(struct domain *d,
>>>>        if ( rc != 0 )
>>>>            return rc;
>>>>
>>>> -    printk("*** LOADING DOMU cpus=%u memory=%"PRIx64"KB ***\n", 
>>>> d->max_vcpus, mem);
>>>> +    printk("*** LOADING DOMU cpus=%u memory=%"PRIu64"KB ***\n", 
>>>> d->max_vcpus, mem);
>>>
>>> I will prefer it to be printed in hex format with 0x prefixed. The
>>> reason being the mem is obtained from device-tree domU's 'memory' prop
>>> where the values are in hex.
>> No, I cannot agree. Refer to booting.txt documentation:
>> "A 64-bit integer specifying the amount of kilobytes of RAM to allocate to 
>> the guest."
>> Also note that in the provided examples, we are using the decimal values.
>> All in all it does not matter the notation, you can provide e.g. "memory = 
>> 131072;" or "memory = 0x20000".
>> I find it a bit odd to print e.g. 0x20000KB and decimal is easier to read.
> By easier, do you mean you can easily figure out how much memory in
> GB/MB/KB you gave to the guest? If so, then I have to disagree. Without
> a calculator, I will find quicker the split.
I guess it depends on the size but you have a valid point.

> 
> If you want to print in decimal, then I think we should split the amount
> in GB/MB/KB. Otherwise, we should stick in hexadecimal (so add 0x).
Ok, I will then just add a prefix.

> 
> Cheers,
> 
> --
> Julien Grall

~Michal