From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37288 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932176AbeAMNRa (ORCPT ); Sat, 13 Jan 2018 08:17:30 -0500 Subject: Patch "x86/pti/efi: broken conversion from efi to kernel page table" has been added to the 4.9-stable tree To: pasha.tatashin@oracle.com, jkosina@suse.cz, steven.sistare@oracle.com Cc: , From: Date: Sat, 13 Jan 2018 14:17:30 +0100 In-Reply-To: <20180111215820.29736-1-pasha.tatashin@oracle.com> Message-ID: <1515849450248243@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/pti/efi: broken conversion from efi to kernel page table to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From pasha.tatashin@oracle.com Sat Jan 13 14:16:28 2018 From: Pavel Tatashin Date: Thu, 11 Jan 2018 16:58:20 -0500 Subject: x86/pti/efi: broken conversion from efi to kernel page table To: steven.sistare@oracle.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, gregkh@linuxfoundation.org, jkosina@suse.cz, hughd@google.com, dave.hansen@linux.intel.com, luto@kernel.org, torvalds@linux-foundation.org Message-ID: <20180111215820.29736-1-pasha.tatashin@oracle.com> From: Pavel Tatashin The page table order must be increased for EFI table in order to avoid a bug where NMI tries to change the page table to kernel page table, while efi page table is active. For more disccussion about this bug, see this thread: http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html Signed-off-by: Pavel Tatashin Reviewed-by: Steven Sistare Acked-by: Jiri Kosina --- arch/x86/include/asm/pgalloc.h | 11 +++++++++++ arch/x86/platform/efi/efi_64.c | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -27,6 +27,17 @@ static inline void paravirt_release_pud( */ extern gfp_t __userpte_alloc_gfp; +#ifdef CONFIG_PAGE_TABLE_ISOLATION +/* + * Instead of one PGD, we acquire two PGDs. Being order-1, it is + * both 8k in size and 8k-aligned. That lets us just flip bit 12 + * in a pointer to swap between the two 4k halves. + */ +#define PGD_ALLOCATION_ORDER 1 +#else +#define PGD_ALLOCATION_ORDER 0 +#endif + /* * Allocate and free page tables. */ --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -142,7 +142,7 @@ int __init efi_alloc_page_tables(void) return 0; gfp_mask = GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO; - efi_pgd = (pgd_t *)__get_free_page(gfp_mask); + efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER); if (!efi_pgd) return -ENOMEM; Patches currently in stable-queue which might be from pasha.tatashin@oracle.com are queue-4.9/x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch