From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH] Map in physical addresses in efi_map_region_fixed Date: Tue, 16 Aug 2016 15:29:33 +0200 Message-ID: <20160816132933.GA11106@nazgul.tnic> References: <1470441575-96065-1-git-send-email-athorlton@sgi.com> <20160815124258.GF30909@codeblueprint.co.uk> <20160815150709.GA6085@nazgul.tnic> <20160816123028.GN30909@codeblueprint.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20160816123028.GN30909@codeblueprint.co.uk> Sender: linux-kernel-owner@vger.kernel.org To: Matt Fleming Cc: Alex Thorlton , linux-kernel@vger.kernel.org, Russ Anderson , Dimitri Sivanich , Mike Travis , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-efi@vger.kernel.org, Dave Young List-Id: linux-efi@vger.kernel.org On Tue, Aug 16, 2016 at 01:30:28PM +0100, Matt Fleming wrote: > That's impossible, because that would mean we loaded the kexec kernel > over the top of physical pages of EFI services. We still need to be > able to invoke EFI services from kexec - we just can't change their > virtual mappings. Which would mean that whatever comes second - kexec reservation or 1:1 mappings - won't work. > This is because of the way that the SGI firmware works and that the > "new" virtual address mappings are usable on SGI+kexec now. My only issue is that we probably should've aimed for avoiding that... > No, some Apple platforms will not boot if SetVirtualAddressMap() > passes 1:1 mappings, and we only enter the firmware via the 1:1 > mappings for EFI mixed mode calls. We're still using the virtual > runtime mappings in the commit you reference below most of the time. ... but reasons like the above are making us run the kexec kernel with the exact-same mappings as the boot kernel. Probably not really a big deal since we have our own pagetable... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --