Re: [PATCH] hw/pci-host/pnv_phb4: fix guest-triggerable abort on 8-byte config access

+ Jishnu

Thanks Philippe for your inputs.

Hi Aditya,
Are we expecting a v2 or a follow-up patch here?
Needs your ack, thanks.

regards,
Harsh

On 05/08/26 9:23 pm, Philippe Mathieu-Daudé wrote:
> On 5/8/26 15:53, Nikhil Kumar Singh wrote:
>> Hi Philippe,
>>
>> Thanks for the review.
>>
>> 1. Regarding MIN(size, 4): I avoided this because silently truncating 
>> an 8-byte guest read to 4 bytes leaves the upper 32 bits 
>> unpredictable, which might mask guest OS bugs. Returning ~0ull 
>> explicitly matches standard PCI behaviour for invalid reads and is safer.
> 
> OK.
> 
>> 2. Regarding pci_host_data_le_ops: I agree this is the right way to 
>> handle it. However, PHB_CONFIG_DATA is currently interleaved inside 
>> the larger big-endian PHB4 MMIO region. Moving it to generic little- 
>> endian ops requires a memory region refactor using overlays.
> 
> Yeah, "if it ain't broke, don’t fix it", so let's keep maintaining
> something old and different.
> 
>> Since this patch addresses an immediate DoS crash, I kept the scope 
>> minimal.
> 
> OK, no objection to your patch, just my 2 cents ;)
> 
>> Memory region refactoring can be picked up as a separate follow-up patch.
>>
>> Regards,
>> ~ Nikhil
>>
>