From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f51.google.com (mail-wm1-f51.google.com [209.85.128.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2AAE836A03A for ; Sat, 29 Aug 2026 05:50:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787982627; cv=none; b=iAc018XbKQgYqTBHQtEMO7FCM2xgajMIGK28Sr8wx3FurowyIM8SZN4+cHRKvQ1z1DXDFXYecldZSAmmf0GEmc95emNoyD7GDU+XxZ+nuoUoraoR3hqa23qN2qftPJNYiDCkqHQ6RQxu8krukIviavbId8RDldk/u0aecPQNPfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787982627; c=relaxed/simple; bh=aru3gpZckcqhzLmD1P2HSOiefupvneO2iUB5oqNw958=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nv1FuCKWjV4nz97I4W0MjgLJml3I7BIDvEmRb8Om2Ysbo/Pr7TTi0oYDmdytO/MYn7/sArivk6moRUdGf7CkWhulIGrAxIT7TulCjbtC/IqWzNexUe523C2TsMwrdRNHTmBRmCYs2zueNlut+BoG7TLQiHw8pFjW5aD5OKpP/2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=GjAKPDiH; arc=none smtp.client-ip=209.85.128.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GjAKPDiH" Received: by mail-wm1-f51.google.com with SMTP id 5b1f17b1804b1-495590dde14so15687475e9.0 for ; Fri, 28 Aug 2026 22:50:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787982623; x=1788587423; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=JBWN6j8OnBuuPy0FKZmRrD0AlW+PPdIjJrnUe6crviU=; b=GjAKPDiHLPFArNBvKMyLefBHvLNucNuoYwePhbhaGfb4sQLyCCXC09en94CFYNO1pC eH6fZ565GQSH1oU4WpjLr8tF+Xndp9TpBI49LrxFH2fWKaoRHfIGnH953h/MN26lUCuO Ergud5VSUpWpV+wWQyQJFmYNBqIPtQII/+xcudqKpXSB/Jzodj/0kc9eEkAlpcvlyc3R nR8FGnBuiZAuj/6LH9j/8jR/cj6+1bm8UMLvJDKGhE5w3DccTzdAyeE7OY9K2ebRzxKP zwVUOXuu5QdwZFPyirRxjYh7vSYQ0d721cBj6YGS98j18ct50NB67Vmk08T8F60LKVPW lZ/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787982623; x=1788587423; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=JBWN6j8OnBuuPy0FKZmRrD0AlW+PPdIjJrnUe6crviU=; b=DJEfCZxbRYs+8J4l9+tl+MF96wc74l/n5xTU4p6incd3UspzMI7rkT2jC3S6gZk2V9 uK1JHz5Ho3lCR0Q07gNvjk57O4zAy7Na1XcDNmjSjVQeo1ncLiFFl18kuH53QeLtxhEa obRp0+Kq8zbpXRjN7fPZ4UGVjxvTmqewh7EQ6repC6WYNrECPrad+YknyoxSK0E4hmTB +LKv+5VDfVPuH2gwwdPxuV6c8Bv+Xzit9wSAweLhRbIuAgn6aKRGbxWXfvP4P2dtbzG8 7/9IbWQhZNNfj15qiV/XlCJlNoBoA6XxXPPBOhrqtPrm0htN9NPaenW2CXc1qzzrqYpY iNSw== X-Forwarded-Encrypted: i=1; AHgh+RqZyQDV1MfMY5oi1FEM+O1bPe3P7mIFuqeZexhsoZWndN9BuYPJ5q74Zd6EhLPUnDOYjVGt/L1Y7N1JnfXGW1c=@vger.kernel.org X-Gm-Message-State: AFuF++kTqxg4TUe7OsLtiLFLCcGs/f8+7FsSu8GQWgbiZNADXo9UGeSy oPuZG6562TQhdaLp1hKZKgPtuGD/+OXh38deubbXA88K0Nyt+mcjzMjG X-Gm-Gg: AR+sD12cZpiVBXW/KpLelFDJziqLyb8H1kx0SUINzI3Rv4ibeLGGdqIpO9jjwQLKGvZ nfyXttSjP4rjeu+DD1g8sD4+/B0JUaJBKiQAthgsrDE2Xc67+qkspM3UVmdIQ4kmhAOpAmW1ezf X64UDKOJGDwTzQ8ct6NqREXMsHpWV9zsB7cgJmILsw19hrUxPOopeE3MvmZ+hZ5tantqtaPGKTj d1TvfeJi3yUiZ0zcdimCirJxLA82M0yk2SzClHDLh6HvJBFfXb4hLFIxZ8hVTRzEjordOJtBsoA A8kaeNiB8Qzt61OUrzp0bdiu6X+xBP68GK4dNqIhdhtCVw1rxcmPwVY5ADWt0juyMwLLlSBg9f8 r9h9WxtRRTY1Rw0r0D6GyYIV2JWk/Z3VCqEhUHnppyyXgaH7BgGRDsXx1ezpZdQHIgMf0DrljW6 lEMd8i6nqVGeHjT45Cf9iJJRvV+CJizRLhoOrucsHIxSYPLfy+3H25rQ9/AZ1QZAF8Quz/2SnOx ABnMha7L6AuzUnSr/dsRiUj2gmibDH2egn2anqgiX/QsOyhbKtxidw+HA8nkr5Ip+tyj2+JkW65 YceeEjKDqCC5u+VH0fYy X-Received: by 2002:a05:600c:a47:b0:499:be9e:49c8 with SMTP id 5b1f17b1804b1-49b91c50957mr150918935e9.13.1787982622515; Fri, 28 Aug 2026 22:50:22 -0700 (PDT) Received: from localhost.localdomain (dynamic-077-007-015-136.77.7.pool.telefonica.de. [77.7.15.136]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49cca3e642dsm35357485e9.2.2026.08.28.22.50.21 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 28 Aug 2026 22:50:22 -0700 (PDT) From: Karl Mehltretter To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev Cc: Karl Mehltretter , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Paolo Bonzini , Sean Christopherson , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH 1/2] KVM: arm64: Return -EINVAL for an empty SMCCC filter range at base 0 Date: Sat, 29 Aug 2026 07:48:55 +0200 Message-Id: <20260829054856.70549-2-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260829054856.70549-1-kmehltretter@gmail.com> References: <20260829054856.70549-1-kmehltretter@gmail.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit kvm_smccc_set_filter() only rejects a range if its inclusive end, base + nr_functions - 1, is below base. That catches an empty range (nr_functions == 0) at every nonzero base, but at base 0 the end wraps to U32_MAX and KVM tries to insert [0, U32_MAX], which overlaps the reserved Arm Architecture Calls ranges. KVM_ARM_VM_SMCCC_FILTER then returns -EEXIST instead of the -EINVAL that the smccc_filter selftest expects for an empty range. Reject a zero function count explicitly. Tested with a userspace reproducer on an arm64 VHE host under QEMU TCG: EEXIST before, EINVAL after. Fixes: 821d935c87bc ("KVM: arm64: Introduce support for userspace SMCCC filtering") Assisted-by: LLM Signed-off-by: Karl Mehltretter --- arch/arm64/kvm/hypercalls.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index b11b8821c9fb..dfa25bb6f25d 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -185,7 +185,8 @@ static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user start = filter.base; end = start + filter.nr_functions - 1; - if (end < start || filter.action >= NR_SMCCC_FILTER_ACTIONS) + if (!filter.nr_functions || end < start || + filter.action >= NR_SMCCC_FILTER_ACTIONS) return -EINVAL; mutex_lock(&kvm->arch.config_lock); -- 2.39.5 (Apple Git-154)