From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65F43CCA47F for ; Fri, 10 Jun 2022 09:35:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346678AbiFJJfr (ORCPT ); Fri, 10 Jun 2022 05:35:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348646AbiFJJfp (ORCPT ); Fri, 10 Jun 2022 05:35:45 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38412215 for ; Fri, 10 Jun 2022 02:35:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id EB075B83355 for ; Fri, 10 Jun 2022 09:35:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1C7DC34114; Fri, 10 Jun 2022 09:35:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654853741; bh=Hy44ebNJtdRyimKZ0wHSwqsYAjTWcKc/GaO9BGQt+IA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MNRMoinxrv8cCVH6ckQlh6bO6wu08NptrV2+KQU5zwQgQbIaZHTwZ+T2rvno+lQBk 7ZrbiVH8zRilig5kXhd8FxZT+LsXLi96I5bRpd0XJ8A6mfxKEPcv7UsNim9eurJmxG nOPgtRag4pOeERMnLVwcr8205DMQXpoDGvEBlOpfNFTlunHZjB5fXnxXp1lYreQT2L 7hPiFPyYQmZNBKqdvawNGqBOoVlqcJf4+7pr13u6oK1/Zna7Ipg22PP2qRhy7Z3+6L AxM9G30f0Vj/tUOWNSZgakU/yNXLAWSvjDDviHUEwCr/qD7Y8IEfDzY1j0vaIFqwaV ppdlhgHac4gJA== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nzawr-00H6Dt-Nl; Fri, 10 Jun 2022 10:28:57 +0100 From: Marc Zyngier To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: James Morse , Suzuki K Poulose , Alexandru Elisei , Oliver Upton , Will Deacon , Fuad Tabba , Quentin Perret , Mark Brown , Reiji Watanabe , kernel-team@android.com Subject: [PATCH v2 16/19] KVM: arm64: Add build-time sanity checks for flags Date: Fri, 10 Jun 2022 10:28:35 +0100 Message-Id: <20220610092838.1205755-17-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220610092838.1205755-1-maz@kernel.org> References: <20220610092838.1205755-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, oupton@google.com, will@kernel.org, tabba@google.com, qperret@google.com, broonie@kernel.org, reijiw@google.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Flags are great, but flags can also be dangerous: it is easy to encode a flag that is bigger than its container (unless the container is a u64), and it is easy to construct a flag value that doesn't fit in the mask that is associated with it. Add a couple of build-time sanity checks that ensure we catch these two cases. Reviewed-by: Fuad Tabba Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_host.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ffbeb5f5692e..6a37018f40b7 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -433,8 +433,20 @@ struct kvm_vcpu_arch { #define __unpack_flag(_set, _f, _m) _f #define unpack_vcpu_flag(...) __unpack_flag(__VA_ARGS__) +#define __build_check_flag(v, flagset, f, m) \ + do { \ + typeof(v->arch.flagset) *_fset; \ + \ + /* Check that the flags fit in the mask */ \ + BUILD_BUG_ON(HWEIGHT(m) != HWEIGHT((f) | (m))); \ + /* Check that the flags fit in the type */ \ + BUILD_BUG_ON((sizeof(*_fset) * 8) <= __fls(m)); \ + } while (0) + #define __vcpu_get_flag(v, flagset, f, m) \ ({ \ + __build_check_flag(v, flagset, f, m); \ + \ v->arch.flagset & (m); \ }) @@ -442,6 +454,8 @@ struct kvm_vcpu_arch { do { \ typeof(v->arch.flagset) *fset; \ \ + __build_check_flag(v, flagset, f, m); \ + \ fset = &v->arch.flagset; \ if (HWEIGHT(m) > 1) \ *fset &= ~(m); \ @@ -452,6 +466,8 @@ struct kvm_vcpu_arch { do { \ typeof(v->arch.flagset) *fset; \ \ + __build_check_flag(v, flagset, f, m); \ + \ fset = &v->arch.flagset; \ *fset &= ~(m); \ } while (0) -- 2.34.1