From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756637AbaH0Kap (ORCPT ); Wed, 27 Aug 2014 06:30:45 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:56488 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756002AbaH0Kan (ORCPT ); Wed, 27 Aug 2014 06:30:43 -0400 Date: Wed, 27 Aug 2014 11:30:38 +0100 From: Matt Fleming To: Harald Hoyer Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org Subject: Re: [PATCH V2] efi_high_alloc: use EFI_ALLOCATE_MAX_ADDRESS Message-ID: <20140827103038.GB28116@console-pimps.org> References: <1408715303-2215-1-git-send-email-harald@redhat.com> <1408967732-2381-1-git-send-email-harald@redhat.com> <20140825130724.GT29733@console-pimps.org> <53FB4952.1090104@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53FB4952.1090104@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 25 Aug, at 04:33:54PM, Harald Hoyer wrote: > > So is that ok, if other callers of efi_high_alloc() get an address > > 4GB? Yeah, the issue at hand is that some x86 EFI firmware cannot perform a file read into a buffer above 4G. The actual allocation works fine. If other callers want a high address buffer, they're not going to hit that issue. We've no reason to believe that this bug affects arm64 at all, for instance. Working around this problem in efi_high_alloc() gives the impression that there's something wrong with AllocatePages(), which isn't the case. > Will the buggy EFI implementation work with the usage of the other > caller's allocated memory? Or will they run into the same issues as > the initramfs loader? Based on the information we've gathered so far, there's no reason to believe other callers will hit the same issue as the file reading code. -- Matt Fleming, Intel Open Source Technology Center