Re: [libvirt] [PATCH 2/2] qemu: command: Don't format image properties for empty -drive

On Wed, Jan 16, 2019 at 01:12:01PM +0100, Peter Krempa wrote: > On Wed, Jan 16, 2019 at 09:52:42 +0000, Daniel Berrange wrote: > > On Wed, Jan 16, 2019 at 10:42:10AM +0100, Peter Krempa wrote: > > > If a -drive has no image, using image properties makes qemu whine that > > > they should not be used. > > > > > > This patch stops formating cache/readonly/... for empty drives > > > for the pre-blockdev syntax. Unfortunately those parameters can't be > > > added later when inserting media, but on the other hand qemu will start > > > with an empty drive. > > > > So, IIUC, if you need to set cache/readonly/etc when inserting media, > > then the fix is simply to use a QEMU that supports blockdev? > > Yes. With blockdev we setup the cache modes as the user > wishes/configures. Currently AFAIK the user would not get the required > mode anyways. > > This should not be any problem for cdroms. Floppy drives might end up > with incorrect cache mode. If someone cares about data integrity of the floppy drives on host crash, I think they need to re-evaluate their decision making approach ;-P