From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH] KVM: arm64: Stop printing about MMIO accesses where ISV==0
Date: Wed, 25 Oct 2023 08:25:07 +0000 [thread overview]
Message-ID: <ZTjQ43gpJUvfh6rG@linux.dev> (raw)
In-Reply-To: <86il6v3z6d.wl-maz@kernel.org>
On Wed, Oct 25, 2023 at 09:04:58AM +0100, Marc Zyngier wrote:
[...]
> While I totally agree that this *debug* statement should go, we should
> also replace it with something else.
>
> Because when you're trying to debug a guest (or even KVM itself),
> seeing this message is a sure indication that the guest is performing
> an access outside of memory. The fact that KVM tries to handle it as
> MMIO is just an implementation artefact.
>
> So I'd very much welcome a replacement tracepoint giving a bit more
> information, such as guest PC, IPA being accessed, load or store. With
> that, everybody wins.
Aren't we already covered by the kvm_guest_fault tracepoint? Userspace
can filter events on ESR to get the faults it cares about. I'm not
against adding another tracepoint, but in my experience kvm_guest_fault
has been rather useful for debugging any type of guest fault.
--
Thanks,
Oliver
next prev parent reply other threads:[~2023-10-25 8:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-24 21:07 [PATCH] KVM: arm64: Stop printing about MMIO accesses where ISV==0 Oliver Upton
2023-10-25 8:04 ` Marc Zyngier
2023-10-25 8:25 ` Oliver Upton [this message]
2023-10-25 8:41 ` Marc Zyngier
2023-10-26 8:23 ` Oliver Upton
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