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

[Samuel Thibault]

Stefano Stabellini, le Wed 25 Mar 2009 16:19:58 +0000, a écrit :
> Avi Kivity wrote:
> 
> > Stefano Stabellini wrote:
> >> Hi all,
> >> after the recent introduction of dma_buf_prepare we stopped honoring
> >> IDE_DMA_BUF_SECTORS (the guest can issue dma requests with a greater
> >> total length than IDE_DMA_BUF_SECTORS).
> >> This patch adds the IDE_DMA_BUF_SECTORS limit back in place.
> >>
> >> Comments are welcome.
> >>   
> > 
> > Aren't 64K sector requests legal?
> > 
> > Looking at ide_cmd_lba48_transform().
> > 
> 
> 
> I am not sure about that, but I would think not since we define 
> MAX_MULT_SECTORS 16
> If I change MAX_MULT_SECTORS, am I supposed to see smaller dma requests?

Do not confuse things. MAX_MULT_SECTORS is for multi-sectors PIO, not
for DMA.

Samuel