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Date: Tue, 22 Sep 2026 09:49:18 -0700
From: Oliver Upton <oupton@kernel.org>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Joey Gouly <joey.gouly@arm.com>,
	Steffen Eiden <seiden@linux.ibm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Mark Rutland <mark.rutland@arm.com>,
	Fuad Tabba <fuad.tabba@linux.dev>,
	Randy Dunlap <rdunlap@infradead.org>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
	kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
	Jack Thomson <jackabt@amazon.com>,
	Jack Thomson <jackabt.amazon@gmail.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Vincent Donnefort <vdonnefort@google.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
	Sean Christopherson <seanjc@google.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Leo Soares Passos <Leo.Bras@arm.com>,
	Wei-Lin Chang <weilin.chang@arm.com>
Subject: Re: [PATCH v3 01/14] KVM: Allow architectures to disallow pre-fault
Message-ID: <arKxjsxuO1F5ExrY@kernel.org>
References: <20260922-kvm-arm-prefault-v3-0-787bd3bc7e3f@kernel.org>
 <20260922-kvm-arm-prefault-v3-1-787bd3bc7e3f@kernel.org>
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In-Reply-To: <20260922-kvm-arm-prefault-v3-1-787bd3bc7e3f@kernel.org>

Hi Lorenzo,

On Tue, Sep 22, 2026 at 03:17:55PM +0100, Lorenzo Stoakes (ARM) wrote:
> +bool __weak kvm_arch_vcpu_allow_pre_fault_memory(struct kvm_vcpu *vcpu)
> +{
> +	return true;
> +}
> +
>  void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
>  {
>  	int nr_vcpus, start, i, idx, yielded;
> @@ -4365,6 +4370,9 @@ static int kvm_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
>  	    range->gpa + range->size <= range->gpa)
>  		return -EINVAL;
>  
> +	if (!kvm_arch_vcpu_allow_pre_fault_memory(vcpu))
> +		return -ENOEXEC;
> +

nit: it'd be better to let the arch hook return an error of its choosing
but in reality this is only going to be used by arm64.

Not worth a respin on its own though.

Thanks,
Oliver