From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Brad Campbell <lists2009@fnarfbargle.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>,
kvm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: KVM broken after suspend in most recent kernels.
Date: Tue, 26 May 2020 22:13:55 -0700 [thread overview]
Message-ID: <20200527051354.GL31696@linux.intel.com> (raw)
In-Reply-To: <a45bc9d7-ad0b-2ff0-edcc-5283f591bc10@fnarfbargle.com>
On Mon, May 25, 2020 at 09:15:57PM +0800, Brad Campbell wrote:
> >When you mean that KVM is broken after suspend, you mean that you can't
> >start new VMs after suspend, or do VMs that were running before suspend
> >break? I see the later on my machine. I have AMD system though, so most
> >likely this is another bug.
> >
> >Looking at the commit, I suspect that we indeed should set the IA32_FEAT_CTL
> >after resume from ram, since suspend to ram might count as a complete CPU
> >reset.
> >
>
> One of those "I should have clarified that" moments immediately after I
> pressed send. I've not tried suspending with a VM running. It's "can't start
> new VMs after suspend".
Don't bother testing suspending with a VM, the only thing that will be
different is that your system will hang on resume instead when running a
VM. If there are active VMs, KVM automatically re-enables VMX via VMXON
after resume, and VMXON is what's faulting.
Odds are good the firmware simply isn't initializing IA32_FEAT_CTL, ever.
The kernel handles the boot-time case, but I (obviously) didn't consider
the suspend case. I'll work on a patch.
next prev parent reply other threads:[~2020-05-27 5:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 4:50 KVM broken after suspend in most recent kernels Brad Campbell
2020-05-24 10:43 ` Brad Campbell
2020-05-25 11:46 ` Maxim Levitsky
2020-05-25 13:15 ` Brad Campbell
2020-05-27 5:13 ` Sean Christopherson [this message]
2020-05-27 12:28 ` Maxim Levitsky
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