From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=2607:f8b0:4001:c06::236; helo=mail-io0-x236.google.com; envelope-from=ard.biesheuvel@linaro.org; receiver=edk2-devel@lists.01.org Received: from mail-io0-x236.google.com (mail-io0-x236.google.com [IPv6:2607:f8b0:4001:c06::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 65DAA21F3C198 for ; Tue, 10 Oct 2017 13:42:02 -0700 (PDT) Received: by mail-io0-x236.google.com with SMTP id j17so180100iod.5 for ; Tue, 10 Oct 2017 13:45:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=qVYkwk7jzpiaBd4+5TXxaacwmC/lCc1enQTVg/2PHgI=; b=fqiN7N5nTrepUqydg/kAPp6FDG2PNk/+zWPdKAUJoEMPbGp85BOZHtRmoAL0KakCIN BRSt7ozpEL4fk8quZT2i/15X6fNzNe5uz7OoqVwHaqtoYPrTZsQHk+vXaptLbgxLpL2y afF2NQOYkTSh/PmlApmNm/9CcHAGD8WAaVVMo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=qVYkwk7jzpiaBd4+5TXxaacwmC/lCc1enQTVg/2PHgI=; b=Bl9uvHEgbfBEh9LQCH3dq6wBS+/43udUQUZ5UsTU83gkrtda9dKITfISbCtLTmxqdY hyqY8PneSXyoBaP3kq2Ai4MP6v7eiSVECAbtCuwaZmAcNAF8MlkATBRyUjA+pwpVIC7D sVYfT09dcXVLBv8Ys3EMyZcK6lf3a645jwsAPiWXfMqw87Un7tOUV+Kql9fLg5wL8IiA XtR7Hro9r+fejh+IKjTkRY2TPKHVe7SGmZsmqPrfqIoVDuM+8C0J0sne/tuVh+Ppf8wq wYr7U2phxCBOWkhh8hLgxG1hVD0a1wqeJSLmfmBFp4MkkIwOnAmCyO7BXEYwRT6mHs3C 6gdg== X-Gm-Message-State: AMCzsaUUdGcNFEnoZk118jMB7QaB3XrJr5V0QznC/bTkDZThJ1VcK/LI kaRMI5DaqBHC6P6MwouZGjq+/lIsBWlhcZQbVSI3pg== X-Google-Smtp-Source: AOwi7QCgXQZZHQt/e7HTCJU1I1D6D6M0CFW68wQyzHzE43HFnz8Zq1aaJ0BIxF/GyyGq4/bXGgns4l393OnGFIzlVSg= X-Received: by 10.107.15.170 with SMTP id 42mr18522862iop.141.1507668330012; Tue, 10 Oct 2017 13:45:30 -0700 (PDT) MIME-Version: 1.0 Received: by 10.107.131.167 with HTTP; Tue, 10 Oct 2017 13:45:29 -0700 (PDT) In-Reply-To: References: <1507568462-28775-1-git-send-email-mw@semihalf.com> <1507568462-28775-9-git-send-email-mw@semihalf.com> <20171010145353.do7b6msel3d25pyu@bivouac.eciton.net> From: Ard Biesheuvel Date: Tue, 10 Oct 2017 21:45:29 +0100 Message-ID: To: Marcin Wojtas Cc: edk2-devel-01 , Leif Lindholm , Nadav Haklai , Neta Zur Hershkovits , Kostya Porotchkin , Hua Jing , semihalf-dabros-jan Subject: Re: [platforms: PATCH 08/13] Marvell/Armada: Modify GICC alias X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Oct 2017 20:42:02 -0000 Content-Type: text/plain; charset="UTF-8" On 10 October 2017 at 15:56, Marcin Wojtas wrote: > Hi Ard, > > 2017-10-10 16:53 GMT+02:00 Leif Lindholm : >> On Mon, Oct 09, 2017 at 07:00:57PM +0200, Marcin Wojtas wrote: >>> From: Ard Biesheuvel >>> >>> The GIC architecture mandates that the CPU interface, which consists >>> of 2 consecutive 4 KB frames, can be mapped using separate mappings. >>> Since this is problematic on 64 KB pages, the MMU-400 aliases each >>> frame 16 times, and the two consecutive frames can be found at offset >>> 0xf000. This patch is intended to expose correct GICC alias via >>> MADT, once ACPI support is added. >> >> I'm afraid I don't quite understand this message. >> >> The change seems to be that the InterfaceBase moves from the first 4KB >> alias inside a 64KB page to the last alias within the same page. >> That seems valid, but I don't see how it resolves anything described >> in this message? >> Because now, GICC + 4 KB will point at the second frame, and so the two frames appear adjacently, and precisely 4 KB apart. And at the same time, they are still covered by distinct 64 KB pages so it even works when running the OS with 64k pages.