[Xen-devel] [BUG] altp2m from domU crashes the host

[Matt Leinhos <matt@xxxxxxxxxx>]

Hello,

I am working on a Linux driver that exercises the altp2m interface from
a guest VM. Unfortunately, something goes horribly wrong and I end up
crashing the Xen host.

dom0 is Ubuntu 16.04; the domU guest is running Centos with Linux kernel
3.10.0-327.

Following these steps on a domU guest that's running on Xen 4.8.0-rc4
causes the attached crash.

1. Set a dummy handler for #VE in the guest IDT.
2. Enable altp2m (HVMOP_altp2m_set_domain_state)
3. Create a new altp2m view (HVMOP_altp2m_create_p2m)
4. Enable altp2m vcpu notification (HVMOP_altp2m_vcpu_enable_notify)

The host crash happens immediately. I've also seen a delayed host crash
with Xen 4.6, but I'm focusing on the 4.8 RC here.

I don't know exactly which step causes the crash. I'll continue my
investigation today.

I'll work on a sample driver to exercise the crash if that's helpful.

Regards,
Matt Leinhos
Star Lab
https://starlab.io

Attachment: altp2m_crash.log
Description: Text Data

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