Re: [Qemu-devel] [PATCH] honor IDE_DMA_BUF_SECTORS

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Stefano Stabellini wrote:

>> Anyway I think IDE_DMA_BUF_SECTORS was a qemu limitation and did not 
>> model real hardware behaviour.
>>
> 
> 
> Therefore I must assume that we expect qemu to be able to handle any
> kind of dma request coming from the guest, which at the moment is
> limited to 64K sectors, am I right?

I checked the ide driver in the kernel and it assumes that the max
sectors is either 256 or 64K depending on lba support, exactly as qemu does.


So now my question is: if I want to reduce the maximum dma request size
inside qemu, given that I must fill correctly the guest provided sg
list, is it OK to use IDE_DMA_BUF_SECTORS in dma_buf_prepare as I have
done in my patch?

I don't see any other possible solution, but if you have any other
suggestion you are welcome to let me know.