QEMU-KVM guest rootfs read-only issue

Question

While setting up kernel environment using qemu, I can boot into guest, but rootfs is mount as 'read-only filesystem' . Thus simple command like touch ~/a.txt fails inside guest.

I tried below with and without sudo permission without any success.

qemu-system-x86_64 -kernel arch/x86/boot/bzImage -drive file=~/fs.img,index=0,media=disk,format=raw -append "root=/dev/sda" --enable-kvm

Even after changing ~/fs.img permission from 644 to 666

$ ls -l ~/btrfs.img
-rw-rw-rw- 1 laks laks 1073741824 Dec 22 11:29 ~btrfs.img

Any thoughts on what am i missing here? thanks.

Answer 1

I found the solution after some more google searching. Append rw to the root device. Use "root=/dev/sda rw" instead of "root=/dev/sda"