Re: [Qemu-devel] [PATCH] memory: do not do out of bound notification

[Paolo Bonzini]

On 20/06/19 14:59, Peter Xu wrote:
> I feel like this can be problematic.  I'm imaging:
> 
> start=0x1000_0000, size=0x1000_1000
> 
> This will get size=0x1000 but actually we can do size=0x1000_0000 as
> the first.

Right, we can do:

/*
 * If a naturally aligned region starting at "start" ends before "end",
 * use it.  Otherwise, keep the lowest bit of size.
 */
if (size > (start & -start))
    size = start & -start;
else
    size = size & -size;

>>
>> +        trace_vtd_as_unmap_whole(pci_bus_num(as->bus),
>> +                                 VTD_PCI_SLOT(as->devfn),
>> +                                 VTD_PCI_FUNC(as->devfn),
>> +                                 entry.iova, size);
> 
> Can move this out because this is a trace only so we don't have
> restriction on mask?
> 
>>
>> -    map.iova = entry.iova;
>> -    map.size = entry.addr_mask;
>> -    iova_tree_remove(as->iova_tree, &map);
>> +        map.iova = entry.iova;
>> +        map.size = entry.addr_mask;
>> +        iova_tree_remove(as->iova_tree, &map);
> 
> Same here?
> 

Yes, I would move these and the iova_tree_remove outside the loop, while
keeping entry's initialization inside looks cleaner.

Paolo