linux-kernel - Re: [PATCH] KVM: x86: Ignore -EBUSY when checking nested events from vcpu

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Message-ID: <176849900220.720093.4821232985877290250.b4-ty@google.com>
Date: Thu, 15 Jan 2026 10:03:28 -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, 
	Alessandro Ratti <alessandro@...5c.net>, 
	syzbot+1522459a74d26b0ac33a@...kaller.appspotmail.com
Subject: Re: [PATCH] KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()

On Thu, 08 Jan 2026 19:06:57 -0800, Sean Christopherson wrote:
> Ignore -EBUSY when checking nested events after exiting a blocking state
> while L2 is active, as exiting to userspace will generate a spurious
> userspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's
> demise.  Continuing with the wakeup isn't perfect either, as *something*
> has gone sideways if a vCPU is awakened in L2 with an injected event (or
> worse, a nested run pending), but continuing on gives the VM a decent
> chance of surviving without any major side effects.
> 
> [...]

Applied to kvm-x86 misc, thanks!

[1/1] KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()
      https://github.com/kvm-x86/linux/commit/ead63640d4e7

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