From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 80FC71C174E; Wed, 21 Aug 2024 15:40:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724254833; cv=none; b=Pi4HojHcf/VTczIQRKTPq3exnNyOaFXNGVqyBQSgPV6bD5umm3EsGYbMnpS/jEw2/Tik2Ru6BXvqMJEV6+2Wx+bQ+TIDMjqyOgEkFF6T7gWefj7AsikmHPLnqEF9PflQTs8t0eQb8mLMHuyRZ6qphSL1i5tfan4oK0W9zd7IJB0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724254833; c=relaxed/simple; bh=mCSJQKRmMj4eH3lcee/RC+ZfT7vVkL1yagLwnVsCNiw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Q3RI1vEeuAI8ejfIlQr1aeMKIm2zWPecjStTODPCThGcjJ69gMS+NG4KvSA5H+dv/Bj6X665syI11WMDvghzP8PrzY9KKm7IEh+E6prqbZpVyWYaVPJEHl/UouS2GwuY1GfwOE6DokV4AmPcBG/RT6xq7wV2sVTBr/3dZ56+xnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DC0F6152B; Wed, 21 Aug 2024 08:40:56 -0700 (PDT) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.37.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F36D33F73B; Wed, 21 Aug 2024 08:40:27 -0700 (PDT) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun Subject: [PATCH v4 23/43] KVM: arm64: Validate register access for a Realm VM Date: Wed, 21 Aug 2024 16:38:24 +0100 Message-Id: <20240821153844.60084-24-steven.price@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240821153844.60084-1-steven.price@arm.com> References: <20240821153844.60084-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The RMM only allows setting the lower GPRS (x0-x7) and PC for a realm guest. Check this in kvm_arm_set_reg() so that the VMM can receive a suitable error return if other registers are accessed. Signed-off-by: Steven Price --- arch/arm64/kvm/guest.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 11098eb7eb44..8066d3f05403 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -783,12 +783,38 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) return kvm_arm_sys_reg_get_reg(vcpu, reg); } +/* + * The RMI ABI only enables setting the lower GPRs (x0-x7) and PC. + * All other registers are reset to architectural or otherwise defined reset + * values by the RMM, except for a few configuration fields that correspond to + * Realm parameters. + */ +static bool validate_realm_set_reg(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) +{ + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE) { + u64 off = core_reg_offset_from_id(reg->id); + + switch (off) { + case KVM_REG_ARM_CORE_REG(regs.regs[0]) ... + KVM_REG_ARM_CORE_REG(regs.regs[7]): + case KVM_REG_ARM_CORE_REG(regs.pc): + return true; + } + } + + return false; +} + int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { /* We currently use nothing arch-specific in upper 32 bits */ if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM64 >> 32) return -EINVAL; + if (kvm_is_realm(vcpu->kvm) && !validate_realm_set_reg(vcpu, reg)) + return -EINVAL; + switch (reg->id & KVM_REG_ARM_COPROC_MASK) { case KVM_REG_ARM_CORE: return set_core_reg(vcpu, reg); case KVM_REG_ARM_FW: -- 2.34.1