[PATCH] KVM: arm64: Fix memory leaks from stage2 pagetable

[Qian Cai]

On Tue, May 31, 2022 at 06:01:58PM +0100, Will Deacon wrote:
> Have you spotted any pattern for when the leak occurs? How are you
> terminating the guest?

It just to send a SIGTERM to the qemu-system-aarch64 process. Origially,
right after sending the signal, it will remove_id/unbind from the vfio-pci
and then bind to the original (ixgbe) driver. However, since the process
might take a while to clean off itself, the bind might failed with -EBUSY.
I could reproduce it a few times one day while was unable to do so some
other days.

Later, we changed the code to make sure the process is disappeard first and
then remove_id/bind/unbind. Apparently, it make harder to reproduce if not
totally eliminate it.