Re: [Qemu-discuss] Suspending a Windows VM with PCI devices attached

[Christopher Snowhill (kode54)]

> On Jul 22, 2018, at 12:53 AM, Maxim Levitsky <address@hidden> wrote:
> 
> On Wed, 2018-07-18 at 23:49 -0700, Christopher Snowhill (kode54) wrote:
>> Is there any possibility of doing this? I realize that suspending is not
>> possible with PCI devices attached, but would it be possible to instead
>> automate the process of hot removing all the PCI devices first, then
>> suspending, then hot adding them back again when resuming the machine? 
>> That'll
>> probably be a firm "no".
> 
> I tried actually to suspends guests with the pci devices attached, and it sort
> of worked (back when I only played with KVM stack (before I joined redhat)).
> 
> In theory you can enable suspend to ram/disk in the guest and use it (google 
> on
> how to do this).
> Then you suspend the guest with 'virsh guest dopmsuspend --target mem/disk' -
> not sure about the exect name, and you wake it with 'dopmwakeup' or so.

Suspending the guest this way is unsupported with OVMF at this time, 
unfortunately.

> 
> While the guest is suspended you can in theory suspend the host. The problem 
> was
> that on my machine that didn't work reliably, most of the times the guest 
> would
> either crash on resume, or crash *after* few munutes, suggesting some kind of
> memory corruption. This is for sure not a supported feature.
> 
> Hot remove/add of the pci devices should work too, I am not aware of any 
> scripts
> that do that automatically. I haven't tried.

I fixed my scripts anyway. The issues I had were:

1) libvirt-guest configured for suspend instead of shutdown.
2) Needed to recreate the guest agent port with virt-manager before the guest 
agent would properly attach to the port and facilitate shutdown.

I'll worry about actually suspending someday in the future.

> 
> Best regards,
>       Maxim Levitsky

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