Anthony Liguori wrote: > Avi Kivity wrote: >> Laurent Vivier wrote: >>> There are remaining issues : libposix-aio uses kernel AIO, so files >>> must be >>> opened using O_DIRECT and buffers must be aligned. libposix-aio is >>> able to >>> manage other cases but this has a performance cost. >>> >>> >> >> Because the guest is also doing dma, the buffers are expected to be >> aligned (it might be different if using pio, but unlikely). > > The IDE emulation always uses a temporary buffer. This is partially > because you cannot always rely on being able to use an offset on > phys_ram_base (when doing user only emulation).
Why is that? > > We can pretty easily patch this code though to use the DMA address > directly instead of the temporary buffer in the non PIO case. We > still have to define a raw_pread() that is capable of emulating sector > alignment though since Linux will use PIO at first. Sure. It seems worthwhile for mainline qemu too. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
