Re: [PATCH v6 1/3] memory: drop guest writes to read-only ram device regions

[Paolo Bonzini]

On 25/05/20 12:54, Philippe Mathieu-Daudé wrote:
>> Not all of them, only those that need to return MEMTX_ERROR.  I would
>> like some guidance from Peter as to whether (or when) reads from ROMs
>> should return MEMTX_ERROR.  This way, we can use that information to
>> device  what the read-only ram-device regions should do.
> Is it only device-specific or might it be partly arch/machine-specific
> (depending on the bus it is mapped)?

Good point, I think that could be handled by propagating the error up in
the memory region hierarchy (i.e. the cached AddressSpaceDispatch radix
tree is used in the common case, but when you have a failure you
percolate it up through the whole hierarchy since that's not a fast path).

Paolo