On 15 Nov 2018, at 06:59, A Z <a...@zegelin.com> wrote:
> 
> This is an issue that involves a combination of different software packages, 
> so my apologies in advance if this is the wrong list to post on.
> 
> I'm experiencing terrible boot times when I assign a large amount of RAM to a 
> VM when used in combination with VIFO/PCI-passthrough.
> 
> On a VM with a Nvidia GTX 970 + USB controller and 24GiB of RAM assigned, the 
> time to the TianoCore splash screen is ~5 minutes. It's then ~30 seconds 
> before Windows 10 begins to boot (spinning dots). During this time, the QEMU 
> CPU core threads are 100% busy.
> 

This sounds quite like a problem I used to have in the past with certain 
versions of OVMF and the Linux kernel. If I remember correctly, some memory 
ranges would get marked as non-cacheable, which resulted in the terrible 
slowdown you describe. The resolution back then was to stick to older versions 
of both the firmware and the kernel.

I still keep around an older version of OVMF that I used until recently - 
edk2.git-ovmf-x64-0-20160714.b1992.gfc3005.noarch.rpm. You could download the 
RPM here and try if it works for you:

https://exa.flopser.de/s/z3cjqFUlZ2gBPCy 
<https://exa.flopser.de/s/z3cjqFUlZ2gBPCy>

Recent QEMU versions started complaining about firmware incompatibilities, so I 
tried the latest RPM from Kraxel (https://www.kraxel.org/repos/jenkins/edk2/ 
<https://www.kraxel.org/repos/jenkins/edk2/>) and it works just fine. The host 
system is Arch Linux with the latest Arch kernel and QEMU.

Cheers,
Hristo

> According to `perf`, the QMU CPU core threads are spending most of their time 
> waiting on a spinlock over kvm->mmu_lock that's created by kvm_zap_gfn_range.
> 
> I'm fairly certain that ~1 year ago (if not longer) the same configuration 
> didn't take this long to boot.
> 
> Regards,
> Adam
> _______________________________________________
> vfio-users mailing list
> vfio-users@redhat.com
> https://www.redhat.com/mailman/listinfo/vfio-users
_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users

Reply via email to