linux-kernel - Re: [PATCH 0/2] KVM: Fix dangling IRQ bypass on x86 and arm64

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Message-ID: <176849868515.717654.3745446194809392090.b4-ty@google.com>
Date: Thu, 15 Jan 2026 10:03:19 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Marc Zyngier <maz@...nel.org>, Oliver Upton <oupton@...nel.org>
Subject: Re: [PATCH 0/2] KVM: Fix dangling IRQ bypass on x86 and arm64

On Tue, 13 Jan 2026 09:46:04 -0800, Sean Christopherson wrote:
> Fix three bugs in one, where KVM can incorrectly leave an IRQ configured
> for bypass after the associated irqfd is deassigned from the VM (if the VMM
> deassigns the irqfd while it's in bypass mode).
> 
> Two of the bugs are recent-ish, one each in x86 and arm64.  The x86 bug is
> the most visible/noisy as it leads to kernel panics on AMD due to SVM's use
> of a per-CPU list to track IRQs/irqfds that are being posted to the vCPU.
> 
> [...]

Applied rather quickly to kvm-x86 fixes, so that these can get as much time in
-next as possible.  I'll wait until next week to send a pull request (hooray
for -rc8), and these are sitting at the top of the branch so I can amend (or
drop) them as needed.

[1/2] KVM: Don't clobber irqfd routing type when deassigning irqfd
      https://github.com/kvm-x86/linux/commit/b4d37cdb77a0
[2/2] KVM: x86: Assert that non-MSI doesn't have bypass vCPU when deleting producer
      https://github.com/kvm-x86/linux/commit/ef3719e33e66

--
https://github.com/kvm-x86/linux/tree/next