Date:   Tue, 7 Feb 2023 12:25:26 +0000
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Steven Price <steven.price@arm.com>
Cc:     kvm@vger.kernel.org, kvmarm@lists.linux.dev,
        Catalin Marinas <catalin.marinas@arm.com>,
        Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
        James Morse <james.morse@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Zenghui Yu <yuzenghui@huawei.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Joey Gouly <joey.gouly@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Christoffer Dall <christoffer.dall@arm.com>,
        Fuad Tabba <tabba@google.com>, linux-coco@lists.linux.dev
Subject: Re: [RFC PATCH 06/28] arm64: RME: ioctls to create and configure
 realms
Message-ID: <Y+JDNkMpk9Y8ReWM@myrica>
References: <20230127112248.136810-1-suzuki.poulose@arm.com>
 <20230127112932.38045-1-steven.price@arm.com>
 <20230127112932.38045-7-steven.price@arm.com>
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On Fri, Jan 27, 2023 at 11:29:10AM +0000, Steven Price wrote:
> +static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap)
> +{
> +	struct kvm_cap_arm_rme_config_item cfg;
> +	struct realm *realm = &kvm->arch.realm;
> +	int r = 0;
> +
> +	if (kvm_realm_state(kvm) != REALM_STATE_NONE)
> +		return -EBUSY;

This should also check kvm_is_realm() (otherwise we dereference a NULL
realm).

I was wondering about fuzzing the API to find more of this kind of issue,
but don't know anything about it. Is there a recommended way to fuzz KVM?

Thanks,
Jean