Eduardo Habkost <ehabkost@xxxxxxxxxx> writes: > On Thu, Apr 29, 2021 at 04:52:21PM +0100, Stefan Hajnoczi wrote: >> The scsi=on|off property was deprecated in QEMU 5.0 and can be removed >> completely at this point. >> >> Drop the scsi=on|off option. It was only available on Legacy virtio-blk >> devices. Linux v5.6 already dropped support for it. >> >> Remove the hw_compat_2_4[] property assignment since scsi=on|off no >> longer exists. Old guests with Legacy virtio-blk devices no longer see >> the SCSI host features bit. >> > > This means pc-2.4 will now break guest ABI if using virtio-blk > devices, correct? > > This looks like a sign we should have deprecated pc-2.4 a long > time ago. The last batch of PC machine type retiring was pc-1.0 to pc-1.3: deprecated in 5.0 (commit 30d2a17b4, Dec 2019), dropped in 6.0 (commit f862ddbb1, just weeks ago). pc-1.3 was a bit over seven years old when we released 5.0. pc-2.4 will be six years old by the time we release 6.1. Fair game? >> Live migrating old guests from an old QEMU with the SCSI feature bit >> enabled will fail with "Features 0x... unsupported. Allowed features: >> 0x...". We've followed the QEMU deprecation policy so users have been >> warned... >> > > Were they really warned, though? People running > "-machine pc-i440fx-2.4" might be completely unaware that it was > silently enabling a deprecated feature. We've gotten better at documenting deprecations, but we're still bad at warning on use of deprecated features. [...]
