Re: [PATCH v2 0/7] kvm: fix latent guest entry/exit bugs

[Paolo Bonzini]

On 1/19/22 20:22, Mark Rutland wrote:
> I wonder, is the s390 guest entry/exit*preemptible*  ?
>
> If a timer IRQ can preempt in the middle of the EQS, we wouldn't balance
> things before a ctx-switch to the idle thread, which would then be able
> to hit this.
>
> I'll need to go audit the other architectures for similar.

They don't enable interrupts in the entry/exit path so they should be 
okay.  RISC-V and x86 have an explicit preempt_disable/enable, while 
MIPS only has local_irq_disable/enable.

(MIPS is a mess of dead code, I have patches to clean it up).

Paolo