jcjgraf

13 ms·

1. 1.▲
   by jcjgraf 1y ago

   Yes, Xen is indeed protected thanks to using Dom0 for running the pendant of Linux's userspace hypervisor (QEMU, fircracker, etc.).This is because transitions to Dom0 lead to a branch predictor flush. See my other comment for more info
2. 2.▲
   by jcjgraf 1y ago

   Please see my other comment where I share more details about VMScape and why Xen is not affected. In short, it is because branch predictor state is flushed when transitioning to Dom0. Indeed, it has nothing to do with type of kernel... And
3. 3.▲
   by jcjgraf 1y ago

   VMScape does not allow an attacker to read memory of Dom0 or the host. Dom0 is safe because branch predictor state is flushed when transitioning to Dom0, and the host is secured as it runs as supervisor, while VMScape only targets userspace
4. 4.▲
   by jcjgraf 1y ago

   Indeed, victim (e.g. userspace hypervisor like QEMU, firecracker, etc) and attacker (e.g. malicious guest) need to run on the same core. But with VMScape this is always give, because a guest runs as the same process as its hypervisor. Befor
5. 5.▲
   by jcjgraf 1y ago

   Author of the VMScape paper here. It's great to see an article highlighting the impact of VMScape on Xen, especially since our paper [1] does not discuss Xen in detail (we only briefly mention it in the blog post [2]). That said, the a