Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752878AbbKGJoQ (ORCPT ); Sat, 7 Nov 2015 04:44:16 -0500 Received: from terminus.zytor.com ([198.137.202.10]:33887 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752819AbbKGJoK (ORCPT ); Sat, 7 Nov 2015 04:44:10 -0500 Date: Sat, 7 Nov 2015 01:43:50 -0800 From: tip-bot for Boris Ostrovsky Message-ID: Cc: linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, mingo@kernel.org, linux@eikelenboom.it, tglx@linutronix.de, hpa@zytor.com Reply-To: tglx@linutronix.de, hpa@zytor.com, boris.ostrovsky@oracle.com, mingo@kernel.org, linux-kernel@vger.kernel.org, linux@eikelenboom.it In-Reply-To: <1446749795-27764-1-git-send-email-boris.ostrovsky@oracle.com> References: <1446749795-27764-1-git-send-email-boris.ostrovsky@oracle.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm: Skip the hypervisor range when walking PGD Git-Commit-ID: f4e342c87776884f0309942a3880ca7e835239f9 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2670 Lines: 69 Commit-ID: f4e342c87776884f0309942a3880ca7e835239f9 Gitweb: http://git.kernel.org/tip/f4e342c87776884f0309942a3880ca7e835239f9 Author: Boris Ostrovsky AuthorDate: Thu, 5 Nov 2015 13:56:35 -0500 Committer: Thomas Gleixner CommitDate: Sat, 7 Nov 2015 10:39:39 +0100 x86/mm: Skip the hypervisor range when walking PGD The range between 0xffff800000000000 and 0xffff87ffffffffff is reserved for hypervisor and therefore we should not try to follow PGD's indexes corresponding to those addresses. While this has always been a problem, with the new W+X warning mechanism ptdump_walk_pgd_level_core() can now be called during boot, causing a PV Xen guest to crash. [ tglx: Replaced the macro with a readable inline ] Fixes: e1a58320a38d "x86/mm: Warn on W^X mappings" Reported-by: Sander Eikelenboom Signed-off-by: Boris Ostrovsky Cc: xen-devel@lists.xen.org Link: http://lkml.kernel.org/r/1446749795-27764-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/dump_pagetables.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 1bf417e..a035c2a 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -358,6 +358,21 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, #define pgd_none(a) pud_none(__pud(pgd_val(a))) #endif +#ifdef CONFIG_X86_64 +static inline bool is_hypervisor_range(int idx) +{ + /* + * ffff800000000000 - ffff87ffffffffff is reserved for + * the hypervisor. + */ + return paravirt_enabled() && + (idx >= pgd_index(__PAGE_OFFSET) - 16) && + (idx < pgd_index(__PAGE_OFFSET)); +} +#else +static inline bool is_hypervisor_range(int idx) { return false; } +#endif + static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, bool checkwx) { @@ -381,7 +396,7 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, for (i = 0; i < PTRS_PER_PGD; i++) { st.current_address = normalize_addr(i * PGD_LEVEL_MULT); - if (!pgd_none(*start)) { + if (!pgd_none(*start) && !is_hypervisor_range(i)) { if (pgd_large(*start) || !pgd_present(*start)) { prot = pgd_flags(*start); note_page(m, &st, __pgprot(prot), 1); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/