Comment 12 for bug 1716028

Your example does work (using -blockdev), but I can't get it to work with
-drive.

$ qemu-system-x86_64 \
   -drive id=d01,file=disk1.img,format=qcow2 \
   -device drive=d01,serial=s01,driver=virtio-blk,index=1,share-rw=on \
   -device drive=d01,serial=s01,driver=virtio-blk,index=2,share-rw=on
warning: TCG doesn't support requested feature: CPUID.01H:ECX.vmx [bit 5]
qemu-system-x86_64: -device drive=d01,serial=s01,driver=virtio-blk,index=1,share-rw=on: Drive 'd01' is already in use because it has been automatically connected to another device (did you need 'if=none' in the drive options?)

## ok, fix that error, add 'if=none' to the -drive.

$ qemu-system-x86_64 \
  -drive id=d01,file=disk1.img,format=qcow2,if=none \
  -device virtio-blk,drive=d01,serial=s01,index=1,share-rw=on \
  -device virtio-blk,drive=d01,serial=s01,index=2,share-rw=on
qemu-system-x86_64: -device drive=d01,serial=s01,driver=virtio-blk,index=1,share-rw=on: Property '.index' not found

## ok, index belongs on the -drive (which I should have known from
## the past, but which seems not the right place). Try that anyway.

$ qemu-system-x86_64 \
  -drive id=d01,file=disk1.img,format=qcow2,if=none,index=1 \
  -device virtio-blk,drive=d01,serial=s01,share-rw=on \
  -device virtio-blk,drive=d01,serial=s01,share-rw=on
qemu-system-x86_64: -device drive=d01,serial=s01,driver=virtio-blk,share-rw=on: Drive 'd01' is already in use by another device

## Huh? Isn't that what I said to explicitly allow with share-rw=on?

Note that I've also tried with 'format=raw'. Is there something I'm
missing to try to use -drive and -device ?

Lastly (if you're still reading), how do you specify the format of
the file to -blockdev ? adding 'format=qcow2' makes qemu complain that
"'format' is unexpected".

Thanks for your time.