From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753309Ab3LQMKd (ORCPT ); Tue, 17 Dec 2013 07:10:33 -0500 Received: from arkanian.console-pimps.org ([212.110.184.194]:48736 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090Ab3LQMKb (ORCPT ); Tue, 17 Dec 2013 07:10:31 -0500 Date: Tue, 17 Dec 2013 12:10:24 +0000 From: Matt Fleming To: Borislav Petkov Cc: Linux EFI , X86 ML , LKML , Borislav Petkov , Matthew Garrett , "H. Peter Anvin" , Dave Young , James Bottomley , Vivek Goyal , Toshi Kani , Arjan van de Ven Subject: Re: [PATCH 3/3] efi: Make efi virtual runtime map passing more robust Message-ID: <20131217121024.GB3145@console-pimps.org> References: <1387236997-26975-1-git-send-email-bp@alien8.de> <1387236997-26975-4-git-send-email-bp@alien8.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1387236997-26975-4-git-send-email-bp@alien8.de> 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 Tue, 17 Dec, at 12:36:37AM, Borislav Petkov wrote: > From: Borislav Petkov > > Currently, running SetVirtualAddressMap() and passing the physical > address of the virtual map array was working only by a lucky coincidence > because the memory was present in the EFI page table too. Until Toshi > went and booted this on a big HP box - the krealloc() manner of resizing > the memmap we're doing did allocate from such physical addresses which > were not mapped anymore and boom: > > http://lkml.kernel.org/r/1386806463.1791.295.camel@misato.fc.hp.com > > One way to take care of that issue is to reimplement the krealloc thing > but with pages. We start with contiguous pages of order 1, i.e. 2 pages, > and when we deplete that memory (shouldn't happen all that often but you > know firmware) we realloc the next power-of-two pages. > > Having the pages, it is much more handy and easy to map them into the > EFI page table with the already existing mapping code which we're using > for building the virtual mappings. > > And, it doesn't matter all that much how much pages we've used as we're > freeing them right after they've fulfilled their purpose at the end of > the function anyway. > > Reported-by: Toshi Kani > Signed-off-by: Borislav Petkov > --- > arch/x86/platform/efi/efi.c | 57 ++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 48 insertions(+), 9 deletions(-) [...] > @@ -794,12 +814,13 @@ void __init old_map_region(efi_memory_desc_t *md) > */ > void __init efi_enter_virtual_mode(void) > { > + pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd); > + unsigned long size, new_memmap_left = 0; > efi_memory_desc_t *md, *prev_md = NULL; > + int count = 0, new_memmap_shift = 0; > void *p, *new_memmap = NULL; > - unsigned long size; > efi_status_t status; > u64 end, systab; > - int count = 0; > > efi.systab = NULL; You sunk my i386 battleship, /home/build/git/efi/arch/x86/platform/efi/efi.c:824:24: error: ‘struct real_mode_header’ has no member named ‘trampoline_pgd’ make[4]: *** [arch/x86/platform/efi/efi.o] Error 1 make[3]: *** [arch/x86/platform/efi] Error 2 -- Matt Fleming, Intel Open Source Technology Center