On Wed, Sep 27, 2017 at 04:32:34PM +0000, 慕 冬亮 wrote: > > > On 09/22/2017 04:02 PM, Reco wrote: > > <dm5pr12mb190060f6a3633e658f56d98fbc...@dm5pr12mb1900.namprd12.prod.outlook.com> > > > > Hi. > > > > On Fri, Sep 22, 2017 at 07:07:28PM +0000, 慕 冬亮 wrote: > >> qemu-system-x86_64 -kernel /boot/vmlinuz-4.12.0-1-amd64 -hda > >> qemu-stretch.img -append "root=/dev/sda1 single" > One small problem I have modified, sda1 => sda. > There is no any partition in image file. > >> > >> However, the result shows that "VFS: unable to mount root fs". > > And that's exactly how it should be. I'm not sure about jessie's kernel, > > but stretch one has ext support built as a module (CONFIG_EXT4_FS=m). > > > > Meaning - if you want to boot from ext2/ext4 filesystem you'll need > > initrd. This qemu invocation does not supply one. > I tried the following command, that uses the default initrd in /boot, > but dead loop "floopy error -5 while reading block 0" > > qemu-system-x86_64 -kernel /boot/vmlinuz-4.12.0-1-amd64 -initrd > /boot/initrd.img-4.12.0-1-amd64 -hda qemu-stretch.img -append > "root=/dev/sda single"
There is other thread at this mailllist that also shows some curious breakage of stock Debian initrd if it's forced to boot from non-partitioned drive. My gut feeling is you can not force it to work unless you rebuild initrd. > >> I learn the method from the following website: > >> > >> https://www.collabora.com/news-and-blog/blog/2017/01/16/setting-up-qemu-kvm-for-kernel-development/ > > I'm genuinely surprised that such method worked for them. > I have learned how to use busybox as basic environment. > Is that any tutorial to show how to make debian debootstrap image as > basic environment? apt-get install vmdebootstrap man vmdebootstrap -- search for SYNOPSIS Reco