On 05/13/2011 11:26 PM, Sasha Levin wrote: > On Fri, 2011-05-13 at 22:34 +0800, Asias He wrote: >> On 05/13/2011 10:07 PM, Sasha Levin wrote: >>> On Fri, 2011-05-13 at 15:46 +0300, Pekka Enberg wrote: >>>> On 5/13/11 5:40 AM, Asias He wrote: >>>>> commit b764422bb0b46b00b896f6d4538ac3d3dde9e56b >>>>> (kvm tools: Add support for multiple virtio-blk) >>>>> removed the VIRTIO_BLK_F_SEG_MAX publishment to guest. >>>>> >>>>> There is no reason we should not support it. Just bring it back. >>>>> >>>>> Signed-off-by: Asias He<asias.hejun@xxxxxxxxx> >>>> >>>> Sasha? >>> >>> I'm not sure why it was removed, must have missed it when updating >>> struct blk_dev. >>> >>> On the other hand, why do we need to limit max segment size? >> >> That's because the number of entries in a scatter-gather operation must >> be less than the entries in the virt queue we can offer. >> > > I thought that since it's the guest who allocates vq buffers and it's > the guest who does the sg ops, it won't attempt to do that. The size of the virt queue (number of entries) is determined by the device (host). > > But if thats the concern, then yes - lets add it to be safe. > -- Best Regards, Asias He -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
