Re: [Qemu-block] [Qemu-devel] [PATCH 4/7] scsi-disk: introduce dma_readv and dma_writev

[xiaoqiang zhao]

在 2016年06月03日 13:22, Mark Cave-Ayland 写道:
> On 03/06/16 03:56, xiaoqiang zhao wrote:
>
> > 在 2016年06月02日 03:07, Mark Cave-Ayland 写道:
> > > On 23/05/16 13:54, Paolo Bonzini wrote:
> > >
> > > > > These are replacements for blk_aio_preadv and blk_aio_pwritev that
> > > > allow
> > > > > customization of the data path.  They reuse the DMA helpers' DMAIOFunc
> > > > > callback type, so that the same function can be used in either the
> > > > > QEMUSGList or the bounce-buffered case.
> > > > >
> > > > > This customization will be needed in the next patch to do zero-copy
> > > > > SG_IO on scsi-block.
> > > > >
> > > > > Signed-off-by: Paolo Bonzini<address@hidden>
> > > > > ---
> > > > >   hw/scsi/scsi-disk.c | 63
> > > > +++++++++++++++++++++++++++++++++++++++++++----------
> > > > >   1 file changed, 52 insertions(+), 11 deletions(-)
> > > Hi Paolo,
> > >
> > > This patch appears to break qemu-system-sparc booting from CDROM with
> > > the following command line:
> > >
> > > ./qemu-system-sparc -cdrom debian-40r4a-sparc-netinst.iso -boot d
> > >
> > > Instead of booting straight into SILO, OpenBIOS hangs when trying to
> > > read from the CDROM device.
> > Paolo:
> >    By using git bisect on master branch , I found this patch also break
> > qemu-system-arm from booting.
> >    command line:
> >   qemu-system-arm -M versatilepb -kernel vmlinuz-3.2.0-4-versatile
> > -initrd initrd.img-3.2.0-4-versatile -hda
> > /home/hitmoon/debian_wheezy_armel_standard.qcow2 -append 'root=/dev/sda1'
> >
> >   The booting process stops at mounting the root partition and after
> > timeout droped into a initramfs shell. The device '/dev/sda1' is
> > presented . I guess it can not read properly from sda1.
> I've just sent through a patch which fixes the issue for me - please
> test and report back!
>
> Paolo - not sure if it's worth a follow-up patch that renames the
> relevant _readv/_writev functions in scsi-disk.c to _preadv/_pwritev to
> try and help avoid such confusion in future?
>
>
> ATB,
>
> Mark.
Mark:
  I can confirm it works for me !