From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data in the clear Date: Fri, 19 May 2017 15:50:32 -0500 Message-ID: References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418211921.10190.1537.stgit@tlendack-t1.amdoffice.net> <20170515183517.mb4k2gp2qobbuvtm@pd.tnic> <4845df29-bae7-9b78-0428-ff96dbef2128@amd.com> <20170518090212.kebstmnjv4h3cjf2@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170518090212.kebstmnjv4h3cjf2-fF5Pk5pvG8Y@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Borislav Petkov Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Brijesh Singh , Toshimitsu Kani , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Matt Fleming , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Alexander Potapenko , "H. Peter Anvin" , Larry Woodman , linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jonathan Corbet , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kasan-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Ingo Molnar , Andrey Ryabinin , Dave Young , Rik van Riel , Arnd Bergmann , Andy Lutomirski , Thomas Gleixner , Dmitry Vyukov , kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "Michael S. Tsirkin" List-Id: linux-efi@vger.kernel.org On 5/18/2017 4:02 AM, Borislav Petkov wrote: > On Wed, May 17, 2017 at 01:54:39PM -0500, Tom Lendacky wrote: >> I was worried what the compiler might do when CONFIG_EFI is not set, >> but it appears to take care of it. I'll double check though. > > There's a efi_enabled() !CONFIG_EFI version too, so should be fine. > >> I may introduce a length variable to capture data->len right after >> paddr_next is set and then have just a single memunmap() call before >> the if check. > > Yap. > >> I tried that, but calling an "__init" function (early_memremap()) from >> a non "__init" function generated warnings. I suppose I can pass in a >> function for the map and unmap but that looks worse to me (also the >> unmap functions take different arguments). > > No, the other way around: the __init function should call the non-init > one and you need the non-init one anyway for memremap_is_setup_data(). > The "worker" function would be doing the loop through the setup data, but since the setup data is mapped inside the loop I can't do the __init calling the non-init function and still hope to consolidate the code. Maybe I'm missing something here... Thanks, Tom >> This is like the chicken and the egg scenario. In order to determine if >> an address is setup data I have to explicitly map the setup data chain >> as decrypted. In order to do that I have to supply a flag to explicitly >> map the data decrypted otherwise I wind up back in the >> memremap_is_setup_data() function again and again and again... > > Oh, fun. >