Re: [RFC PATCH 0/5] Removing support for 32bit KVM/arm host

From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Anders Berg <anders.berg@lsi.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Russell King <linux@arm.linux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>,
	kvm@vger.kernel.org, Suzuki K Poulose <suzuki.poulose@arm.com>,
	Quentin Perret <qperret@google.com>,
	Christoffer Dall <Christoffer.Dall@arm.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 0/5] Removing support for 32bit KVM/arm host
Date: Tue, 11 Feb 2020 15:23:46 +0000	[thread overview]
Message-ID: <20200211152346.GD153117@arrakis.emea.arm.com> (raw)
In-Reply-To: <20200210141324.21090-1-maz@kernel.org>

On Mon, Feb 10, 2020 at 02:13:19PM +0000, Marc Zyngier wrote:
> KVM/arm was merged just over 7 years ago, and has lived a very quiet
> life so far. It mostly works if you're prepared to deal with its
> limitations, it has been a good prototype for the arm64 version,
> but it suffers a few problems:
> 
> - It is incomplete (no debug support, no PMU)
> - It hasn't followed any of the architectural evolutions
> - It has zero users (I don't count myself here)
> - It is more and more getting in the way of new arm64 developments
> 
> So here it is: unless someone screams and shows that they rely on
> KVM/arm to be maintained upsteam, I'll remove 32bit host support
> form the tree. One of the reasons that makes me confident nobody is
> using it is that I never receive *any* bug report. Yes, it is perfect.
> But if you depend on KVM/arm being available in mainline, please shout.
> 
> To reiterate: 32bit guest support for arm64 stays, of course. Only
> 32bit host goes. Once this is merged, I plan to move virt/kvm/arm to
> arm64, and cleanup all the now unnecessary abstractions.
> 
> The patches have been generated with the -D option to avoid spamming
> everyone with huge diffs, and there is a kvm-arm/goodbye branch in
> my kernel.org repository.
> 
> Marc Zyngier (5):
>   arm: Unplug KVM from the build system
>   arm: Remove KVM from config files
>   arm: Remove 32bit KVM host support
>   arm: Remove HYP/Stage-2 page-table support
>   arm: Remove GICv3 vgic compatibility macros

FWIW:

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

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