Re: [Xen-devel] Re: [Qemu-devel] Recursion in cpu_physical_memory_rw

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 15/11/06 2:58 am, "Herbert Xu" <herbert@xxxxxxxxxxxxxxxxxxx> wrote:

>> It isn't always system memory. Some DMA controllers deliberately write to
>> device FIFOs. There are also several devices which map areas of onboard RAM.
>> At minimum you need to make those to use RAM mappings rather than MMIO.
> 
> I'm not suggesting that we change all existing users of cpu_physical_*
> to a new interface that only accessed RAM.  However, for cases where it
> is obvious that only system RAM is intended (e.g., rtl8139), it makes
> sense to bypass MMIO handlers.

Could we add a recursion counter to the memory-access functions, and bail if
it reaches some limit?

 -- Keir



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