linux-kernel - Re: [PATCH] KVM: selftests: fix irqfd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aKzX152737nAo479@linux.dev>
Date: Mon, 25 Aug 2025 14:38:31 -0700
From: Oliver Upton <oliver.upton@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>, Sebastian Ott <sebott@...hat.com>,
	Paolo Bonzini <pbonzini@...hat.com>, Shuah Khan <shuah@...nel.org>,
	kvm@...r.kernel.org, kvmarm@...ts.linux.dev,
	linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: selftests: fix irqfd_test on arm64

On Mon, Aug 25, 2025 at 02:11:30PM -0700, Sean Christopherson wrote:
> On Mon, Aug 25, 2025, Marc Zyngier wrote:
> > On Mon, 25 Aug 2025 20:52:21 +0100,
> > Sean Christopherson <seanjc@...gle.com> wrote:
> > > Is there a sane way to handle vGIC creation in kvm_arch_vm_post_create()?  E.g.
> > > could we create a v3 GIC when possible, and fall back to v2?  And then provide a
> > > way for tests to express a hard v3 GIC dependency?
> > 
> > You can ask KVM what's available. Like an actual VMM does. There is no
> > shortage of examples in the current code base.
> 
> Right, by "sane" I meant: is there a way to instantiate a supported GIC without
> making it hard/painful to write tests, and without having to plumb in arm64
> specific requirements to common APIs?
> 
> E.g. are there tests that use the common vm_create() APIs and rely on NOT having
> a GIC?

Instead of stuffing a GIC in behind vm_create(), I'd rather we have a
specific helper for creating a VM with an irqchip. There's tests in
arm64 that rely on all this generic infrastructure and also need to
select / dimension a GIC appropriately for the test.

The majority of selftests don't even need an irqchip anyway.

Thanks,
Oliver