Re: Commit 'iomap: add support for dma aligned direct-io' causes qemu/KVM boot failures

[Kevin Wolf]

Am 27.12.2022 um 16:58 hat Keith Busch geschrieben:
> On Thu, Sep 29, 2022 at 07:35:43PM +0200, Paolo Bonzini wrote:
> > Seeing the QEMU patch, I agree that it's a QEMU bug though.  I'm surprised
> > it has ever worked.
> > 
> > It requires 4K sectors in the host but not in the guest, and can be worked
> > around (if not migrating) by disabling O_DIRECT.  I think it's not that
> > awful, but we probably should do some extra releases of QEMU stable
> > branches.
> 
> Just wanted to circle back on this. I see the QEMU patch is applied
> starting from the 7.2 release, but nothing on stable. I realize now that
> stable backports and release are not very frequent, so just want to
> check if there's anything I can or should be doing to help get this
> applied for the previous releases. Thanks!

What we should have done is adding a "Cc: qemu-stable@nongnu.org" line
in the commit message and actually CC that list. We can't change the
commit message any more, but I'm CCing the list now.

For reference, we're talking about these commits to be backported:

* a7c5f67a78569f8c275ea4ea9962e9c79b9d03cb
  block: move bdrv_qiov_is_aligned to file-posix

* 25474d90aa50bd32e0de395a33d8de42dd6f2aef
  block: use the request length for iov alignment

However, I'm not sure what the status is in general with stable releases
for QEMU. We used to have one for previous release shortly after the
next release was announced. But not any more for the past few versions.

Michael, do you have any plans for a stable release?

Kevin