On 28.04.2022 17:04, Sean Christopherson wrote:
On Thu, Apr 28, 2022, Maxim Levitsky wrote:
On Thu, 2022-04-28 at 15:27 +0200, Maciej S. Szmigiero wrote:
On 28.04.2022 09:35, Maxim Levitsky wrote:
On Sat, 2022-04-23 at 02:14 +0000, Sean Christopherson wrote:
From: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
Don't BUG/WARN on interrupt injection due to GIF being cleared if the
injected event is a soft interrupt, which are not actually IRQs and thus
Are any injected events subject to GIF set? I think that EVENTINJ just injects
unconditionaly whatever hypervisor puts in it.
That's right, EVENTINJ will pretty much always inject, even when the CPU
is in a 'wrong' state (like for example, injecting a hardware interrupt
or a NMI with GIF masked).
But KVM as a L0 is not supposed to inject a hardware interrupt into guest
with GIF unset since the guest is obviously not expecting it then.
Hence this WARN_ON().
If you mean L0->L1 injection, that sure, but if L1 injects interrupt to L2,
then it should always be allowed to do so.
Yes, L1 can inject whatever it wants, whenever it wants.
I kept the WARN_ON() under the assumption that KVM would refuse to inject IRQs
stuffed by userspace if GIF is disabled, but looking at the code again, I have
no idea why I thought that. KVM_SET_VCPU_EVENTS blindly takes whatever userspace
provides, I don't see anything that would prevent userspace from shoving in a
hardware IRQ.
You both are right, while KVM itself would not inject IRQ with GIF masked and
a nested VMRUN would enable GIF unconditionally, userspace via KVM_SET_VCPU_EVENTS
does not have this restriction.
Will remove this WARN_ON() then.
Thanks,
Maciej
