Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752154AbdCPMQA (ORCPT ); Thu, 16 Mar 2017 08:16:00 -0400 Received: from mail-pg0-f43.google.com ([74.125.83.43]:36086 "EHLO mail-pg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751539AbdCPMP5 (ORCPT ); Thu, 16 Mar 2017 08:15:57 -0400 Date: Thu, 16 Mar 2017 12:15:32 +0000 From: Matt Fleming To: Ard Biesheuvel Cc: Omar Sandoval , Dave Young , Ingo Molnar , "linux-kernel@vger.kernel.org" , kernel-team@fb.com, "kexec@lists.infradead.org" , "linux-efi@vger.kernel.org" Subject: Re: kexec regression since 4.9 caused by efi Message-ID: <20170316121532.GE6261@codeblueprint.co.uk> References: <20170308201616.GC8598@vader> <20170309063806.GB17257@dhcp-128-65.nay.redhat.com> <20170309095408.GA17883@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 741 Lines: 19 On Thu, 09 Mar, at 12:53:36PM, Ard Biesheuvel wrote: > > Hi Omar, > > Thanks for tracking this down. > > I wonder if this is an unintended side effect of the way we repurpose > the EFI_MEMORY_RUNTIME attribute in efi_arch_mem_reserve(). AFAIUI, > splitting memory map entries should only be necessary for regions that > are not runtime memory regions to begin with, and so whether their > virtual mapping address makes sense or not should be irrelevant. > > Perhaps this only illustrates my lack of understanding of the x86 way > of doing this, so perhaps Matt can shed some light on this? Sorry for the delay. Yes, Ard is correct. It's not necessary to split/reserve memory regions that already have the EFI_MEMORY_RUNTIME attribute.