[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Bug 1908489] Re: qemu 4.2 bootloops with -cpu host and nested hyperviso
From: |
Thomas Huth |
Subject: |
[Bug 1908489] Re: qemu 4.2 bootloops with -cpu host and nested hypervisor |
Date: |
Wed, 18 Aug 2021 13:21:04 -0000 |
Looking at the comments here, I assume this has been a bug in the
kernel, not in QEMU, so I'm closing this one now. If you still think
this is something that needs fixing in QEMU, please open a new ticket in
the new bug tracker at https://gitlab.com/qemu-project/qemu/-/issues
instead.
** Changed in: qemu
Status: Incomplete => Invalid
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1908489
Title:
qemu 4.2 bootloops with -cpu host and nested hypervisor
Status in QEMU:
Invalid
Status in qemu-kvm package in CentOS:
Unknown
Bug description:
I've noticed that after upgrading from Ubuntu 18.04 to 20.04 that
nested virtualization isn't working anymore.
I have a simple repro where I create a Windows 10 2004 guest and
enable Hyper-V in it. This worked fine in 18.04 and specifically qemu
<4.2 (I specifically tested Qemu 2.11-4.1 which work fine).
The -cpu arg I'm passing is simply:
-cpu host,l3-cache=on,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time
Using that Windows won't boot because the nested hypervisor (Hyper-V)
is unable to be initialize and so it just boot loops. Using the exact
same qemu command works fine with 4.1 and lower.
Switching to a named CPU model like Skylake-Client-noTSX-IBRS instead
of host lets the VM boot but causes some weird behaviour later trying
to use nested VMs.
If I had to guess I think it would probably be related to this change
https://github.com/qemu/qemu/commit/20a78b02d31534ae478779c2f2816c273601e869
which would line up with 4.2 being the first bad version but unsure.
For now I just have to keep an older build of QEMU to work around
this. Let me know if there's anything else needed. I can also try out
any patches. I already have at least a dozen copies of qemu lying
around now.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1908489/+subscriptions
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Bug 1908489] Re: qemu 4.2 bootloops with -cpu host and nested hypervisor,
Thomas Huth <=