Re: [PATCH] softmmu/physmem: Improve guest memory allocation failure error message

[Philippe Mathieu-Daudé]

On 8/20/21 5:53 PM, David Hildenbrand wrote:
> On 20.08.21 17:52, Philippe Mathieu-Daudé wrote:
>> When Linux refuses to overcommit a seriously wild allocation we get:
>>
>>    $ qemu-system-i386 -m 40000000
>>    qemu-system-i386: cannot set up guest memory 'pc.ram': Cannot
>> allocate memory
>>
>> Slighly improve the error message, displaying the memory size
>> requested (in case the user didn't expect unspecified memory size
>> unit is in MiB):
>>
>>    $ qemu-system-i386 -m 40000000
>>    qemu-system-i386: Cannot set up 38.1 TiB of guest memory 'pc.ram':
>> Cannot allocate memory
>>
>> Reported-by: Bin Meng <bmeng.cn@gmail.com>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>   softmmu/physmem.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
>> index 2e18947598e..2f300a9e79b 100644
>> --- a/softmmu/physmem.c
>> +++ b/softmmu/physmem.c
>> @@ -1982,8 +1982,10 @@ static void ram_block_add(RAMBlock *new_block,
>> Error **errp)
>>                                                    
>> &new_block->mr->align,
>>                                                     shared, noreserve);
>>               if (!new_block->host) {
>> +                g_autofree char *size_s =
>> size_to_str(new_block->max_length);
>>                   error_setg_errno(errp, errno,
>> -                                 "cannot set up guest memory '%s'",
>> +                                 "Cannot set up %s of guest memory
>> '%s'",
>> +                                 size_s,
>>                                    memory_region_name(new_block->mr));
>>                   qemu_mutex_unlock_ramlist();
>>                   return;
>>
> 
> IIRC, ram blocks might not necessarily be used for guest memory ... or
> is my memory wrong?

No clue, this error message was already here.

No problem to change s/guest/block/ although.