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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 42988C25B75 for ; Thu, 23 May 2024 07:56:14 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.728160.1132979 (Exim 4.92) (envelope-from ) id 1sA3Iu-0001lF-GS; Thu, 23 May 2024 07:56:00 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 728160.1132979; Thu, 23 May 2024 07:56:00 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sA3Iu-0001l8-Dy; Thu, 23 May 2024 07:56:00 +0000 Received: by outflank-mailman (input) for mailman id 728160; Thu, 23 May 2024 07:55:59 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sA3It-0001l2-SH for xen-devel@lists.xenproject.org; Thu, 23 May 2024 07:55:59 +0000 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [2a00:1450:4864:20::42f]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id e40aef12-18d9-11ef-90a1-e314d9c70b13; Thu, 23 May 2024 09:55:58 +0200 (CEST) Received: by mail-wr1-x42f.google.com with SMTP id ffacd0b85a97d-354de3c5d00so737834f8f.1 for ; Thu, 23 May 2024 00:55:58 -0700 (PDT) Received: from localhost ([213.195.114.223]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3502b89573csm35903138f8f.29.2024.05.23.00.55.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 May 2024 00:55:57 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: e40aef12-18d9-11ef-90a1-e314d9c70b13 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1716450958; x=1717055758; darn=lists.xenproject.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=utFsS4D+cK7bzRiCAbwpZ2XGU8VFrSx5GfBbC/QBMxs=; b=bIHt4B0+8z9GH/t3FY+G9NLTvV5hjr3bvKeZ5131fcd0UJ0+k/2dXH7YHqPvbYNIWb rjMkv3DZGE4nRwrxa7TE47j3J3ird0d9mB3WibOyqoCBjEqUm2xwe9bMgDlnLNjdk4iN +YGK9PcHaDqxy2SUEoEfORBuGXFFenHSPrh7g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716450958; x=1717055758; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=utFsS4D+cK7bzRiCAbwpZ2XGU8VFrSx5GfBbC/QBMxs=; b=bP2dq+uEKutKBJDHsg4pnCAj7t9+ORdnaWfSUQrFsHlPe3ewQj3q+fxUR9p/StXw+x Mt6XG/cagHC8Lvo6SdyLkHP21X9krmRuURrJXLhoLfQDP2PTYz1AdwHvAbJatsbxsVwa 4otwtx1eU1RbteN7Mh6l4a+lP0BzRuEUqHb1k2e3+stH0EceY90kmxwTHq9x9gp58V2N YfSlxtPBKTLdh2tyNWV+hbrDK6APKJwdbCOOgXal+DrqFZc8yAQ+3Gm58OkUeRrFOpin QzWkgHS6fcdQNDIbYL//ghbMbgHrm4dVrXhSkJaD/98bNGwFR8faahWEDO2TXaVzHOBD /8VA== X-Gm-Message-State: AOJu0YwuII5BpRhN205oRz2zsCKqtXfK6QyzLefBcg0uiimcxON7kVrz IS+hd1YWLQJR6o9LAckF/eudtCJ2zL2nFFA8M2WMiCv8k6WkhTbwyfTLwOAqReY= X-Google-Smtp-Source: AGHT+IE4WSsAWvuTC4CXl2m8B4VSvv2BRdgFxuFm3fBD5BHb0pQ/XLqZGSgtvW+t+mWdURmLJ6YTMQ== X-Received: by 2002:adf:fd4b:0:b0:34c:fd92:3359 with SMTP id ffacd0b85a97d-354f7521b58mr1291595f8f.21.1716450957943; Thu, 23 May 2024 00:55:57 -0700 (PDT) Date: Thu, 23 May 2024 09:55:56 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Stewart Hildebrand Cc: xen-devel@lists.xenproject.org, Volodymyr Babchuk , Stefano Stabellini , Julien Grall , Bertrand Marquis , Michal Orzel Subject: Re: [PATCH v16 1/5] arm/vpci: honor access size when returning an error Message-ID: References: <20240522225927.77398-1-stewart.hildebrand@amd.com> <20240522225927.77398-2-stewart.hildebrand@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240522225927.77398-2-stewart.hildebrand@amd.com> On Wed, May 22, 2024 at 06:59:20PM -0400, Stewart Hildebrand wrote: > From: Volodymyr Babchuk > > Guest can try to read config space using different access sizes: 8, > 16, 32, 64 bits. We need to take this into account when we are > returning an error back to MMIO handler, otherwise it is possible to > provide more data than requested: i.e. guest issues LDRB instruction > to read one byte, but we are writing 0xFFFFFFFFFFFFFFFF in the target > register. Shouldn't this be taken care of in the trap handler subsystem, rather than forcing each handler to ensure the returned data matches the access size? IOW, something like: diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c index 96c740d5636c..b7e12df85f87 100644 --- a/xen/arch/arm/io.c +++ b/xen/arch/arm/io.c @@ -37,6 +37,7 @@ static enum io_state handle_read(const struct mmio_handler *handler, return IO_ABORT; r = sign_extend(dabt, r); + r = r & GENMASK_ULL((1U << dabt.size) * 8 - 1, 0); set_user_reg(regs, dabt.reg, r); (not even build tested) Thanks, Roger.