[pve-devel] applied: [PATCH qemu-server] cfg2cmd/drive: don't use io_uring for krbd with wb/wt cache

Thomas Lamprecht t.lamprecht at proxmox.com
Thu Jul 1 09:41:37 CEST 2021

On 30.06.21 17:18, Stefan Reiter wrote:
> As reported here and locally reproduced:
> https://forum.proxmox.com/threads/efi-vms-wont-start-under-7-beta-with-writeback-cache.91629/
> This configuration is currently broken. Until we figure out how to fix
> it properly, we can just have this (luckily very narrow) config pattern
> fall back to aio=threads as it used to.
> Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
> ---
> I tried my usual QEMU debugging routine, but couldn't figure anything specific
> out - it's not related to EFI, happens on SeaBIOS too, but looking at GDB just
> appears that it's waiting for the io_uring fd to become ready (in ppoll)...
> I did also test with a newer liburing (2.0 from git) but it didn't help.
> Anyway, until I figure it out (which may not happen until the release), let's
> work around with this, we can always roll this back later, as it doesn't break
> migration/snapshots to change 'aio' type.
> The forum post mentioned other SCSI controllers fixing the issue too, but that
> just confuses me even more, and we don't have that information available for
> cheap here, so I just made it fall back for all of them.

weird stuff...

>  PVE/QemuServer.pm | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

applied for now, thanks!

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