linux-kernel - Re: [PATCH] KVM: x86: Retry guest entry on -EBUSY from kvm_check_nested

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Message-ID: <aV1HtKXlePEJ7CJd@google.com>
Date: Tue, 6 Jan 2026 09:34:44 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Alessandro Ratti <alessandro@...5c.net>
Cc: pbonzini@...hat.com, kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzbot+1522459a74d26b0ac33a@...kaller.appspotmail.com
Subject: Re: [PATCH] KVM: x86: Retry guest entry on -EBUSY from kvm_check_nested_events()

On Tue, Jan 06, 2026, Sean Christopherson wrote:
> On Sun, Jan 04, 2026, Alessandro Ratti wrote:
> I'll post the below as part of a series, as there is at least one cleanup that
> can be done on top to consolidate handling of EBUSY,

Gah, I was wrong.  I was thinking that morphing EBUSY to '0' could be moved into
a common helper, but kvm_apic_accept_events() needs to bail immediately on EBUSY,
i.e. needs to see EBUSY, not '0'.

I'll post this as a standalone patch and then try to add WARNs in a separate
series.

> and I'm hopeful that the spirit of the WARN can be preserved, e.g. by
> adding/extending WARNs in paths where KVM (re)injects events.