Re: [Bug 1924912] VirtIO drivers don't work on Windows: "GLib: Too many handles to wait for!" crash

[Michael S. Tsirkin]

So it's a virtio console issue on a windows host.

[#0 init_stage2(2:2)]: VirtIOConsole: Found @ PCI [0000:00:04:00]
[#0 init_stage2(2:2)]: Trying to unregister unused handler (?)
[#0 init_stage2(2:2)]: VirtIOConsole: Multi port is not yet supported!
[#0 init_stage2(2:2)]: VirtIOConsole: cols: 0, rows: 0, max nr ports 0
qemu-system-i386.exe: warning: GLib: Too many handles to wait for!

Laurent?


On Mon, Apr 19, 2021 at 04:30:23PM +0200, Laurent Vivier wrote:
> Le 19/04/2021 à 12:39, Stefan Weil a écrit :
> > I can confirm the issue also with latest official QEMU sources.
> > 
> > Related issue URLs:
> > 
> > https://github.com/tesseract-ocr/tesseract/issues/2838
> > 
> > https://bugs.launchpad.net/qemu/+bug/1924912
> > 
> > Instructions and files required to reproduce the issue:
> > 
> > https://qemu.weilnetz.de/test/bugs/1924912/
> > 
> > Michael, Laurent, maybe you have an idea how to narrow down this issue?
> 
> Could it be related to the number of file descriptors that can differ between 
> linux an windows?
> 
> We have a series of patches that sets the number of queues to the number of 
> vCPU:
> 
> a4eef0711b2c vhost-user-blk-pci: default num_queues to -smp N
> 9445e1e15e66 virtio-blk-pci: default num_queues to -smp N
> 6a558822849f virtio-scsi-pci: default num_queues to -smp N
> 4e5163bd8444 virtio-scsi: introduce a constant for fixed virtqueues
> 1436f32a84c3 virtio-pci: add virtio_pci_optimal_num_queues() helper
> 
> And I think it can have inpact on the number of open file descriptors.
> 
> You can try by specifiying "num_queues=1" with the virtio interfaces on the 
> QEMU command line.
> (ot choose a machine type earlier than 5.2)
> 
> Thanks,
> Laurent