Hi Shannon,I didn't make it clear. With this patchset we still support !VHE systems by choose CONFIG_KVM_ARM_HOST as y and by default CONFIG_KVM_ARM_HOST is y. And during module init, I add a check to avoid wrong usage for kvm module.
On 24/10/2019 11:27, Shannon Zhao wrote:
Curently KVM ARM64 doesn't support to compile as a kernel module. It's
useful to compile KVM as a module.
For example, it could reload kvm without rebooting host machine.
What problem does this solve?
KVM has some funny requirements that aren't normal for a module. On v8.0 hardware it must
have an idmap. Modules don't usually expect their code to be physically contiguous, but
KVM does. KVM influences they way some of the irqchip stuff is set up during early boot
(EOI mode ... not that I understand it).
(I think KVM-as-a-module on x86 is an artifact of how it was developed)
This patchset support this feature while there are some limitations
to be solved. But I just send it out as RFC to get more suggestion and
Curently it only supports for VHE system due to the hyp code section
address variables like __hyp_text_start.
We still need to support !VHE systems, and we need to do it with a single image.
Actually we can limit this feature only working for VHE systems and don't influence !VHE systems.
Also it can't call
kvm_update_va_mask when loading kvm module and kernel panic with below
errors. So I make kern_hyp_va into a nop funtion.
Making this work for the single-Image on v8.0 is going to be a tremendous amount of work.
What is the payoff?