On Mon, Oct 28, 2024 at 09:43:45AM -0700, Raghavendra Rao Ananta wrote:
On Sat, Oct 26, 2024 at 7:53 AM Oliver Upton oliver.upton@linux.dev wrote:
On Sat, Oct 26, 2024 at 08:43:21AM +0100, Marc Zyngier wrote:
I think this would fix the problem you're seeing without changing the userspace view of an erroneous configuration. It would also pave the way for the complete removal of the interrupt notification to userspace, which I claim has no user and is just a shit idea.
Yeah, looks like this ought to get it done.
Even with a fix for this particular issue I do wonder if we should categorically harden against late initialization failures and un-init the vCPU (or bug VM, where necessary) to avoid dealing with half-baked vCPUs/VMs across our UAPI surfaces.
A sane userspace will probably crash when KVM_RUN returns EINVAL anyway.
Thanks for the suggestion. Sure, I'll take another look at the possible things that we can uninitialize and try to re-spin the patch.
Marc,
If you feel userspace_irqchip_in_use is not necessary anymore, and as a quick fix to this issue, we can get rid of that independent of the un-init effort.
It's a good cleanup to begin with, even better that it fixes a genuine bug.
Raghu, could you please test Marc's diff and send it as a patch (w/ correct attribution) if it works? I'm willing to bet that we have more init/uninit bugs lurking, so we can still follow up w/ robustness improvements once we're happy w/ the shape of them.