Re: [PATCH v15 11/11] RFC: fw_cfg: do DMA read operation

[Michael S. Tsirkin]

On Wed, Feb 28, 2018 at 04:41:51PM +0100, Marc-André Lureau wrote:
> I don't know if it's always safe to enable dma in read_raw(), how
> could we know? Is there a check we could use to choose one or ther
> other (and thus avoiding explicit dma/readfn argument)?

IMHO the way to go is not to try to do zero copy.
Allocate a buffer and DMA there, then copy.

-- 
MST