From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49WU1vgtb/e84l1P+Guk/tQntAV9kvuY7k31v5vbUYe8T4Ims/Jfxu1inGrx74vOFwYQ8SM ARC-Seal: i=1; a=rsa-sha256; t=1523293983; cv=none; d=google.com; s=arc-20160816; b=TVQmo5gF2X72hIzGoU8xhIri+dyfCGWt6WeDg2nNxy2wlcmTCDmJU0vDWJUke5mhQB KHe5GCdgXZGqsbODWi1XEvmrAupPGflWzjlKIj35lgpSbFXIPIkQcaUjL4UK1EO6MG37 LATQH3CaQin/wdZ407z1IF14etABEADPjsPfj9agLM9s9kFObn73J5VFW3K9m8H5I/vm L8gFxjHuGF4ynRwe1Wq15Yjbg7/GGc0CRi9P7lIBCXLNQgJmWrTDsNMNPDYHVbT0aM1+ 0ed1UjV7J61grlVm8WTEeIRy3RHVL6k/DTLRtHEQFbsVIKx3gtpxsLmWmtagFCCDpnme BWFA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=precedence:content-disposition:content-transfer-encoding :mime-version:robot-unsubscribe:robot-id:git-commit-id:subject:to :references:in-reply-to:reply-to:cc:message-id:from:sender:date :arc-authentication-results; bh=LYWlzjP8+MoGTwD/gtg1oA9IDM0A57UrFdrLnrdVDsY=; b=CkmlIday9zpYIP87MUxkQUXOjKA2mrhvlnT5/YbGipD9zj97w8v2IF2qmh9l6axhqV uOZq0pxpgUrWneS1+7kONxTZxxIqj85bTi3WIV85xOF27wGXbuhZ+qMDtf5j/Dz85yQV cED8sEK0MwyuarXOSKGIJuPnG8SDYTDEKweoU2ffjpd51F8atENGpbL9upSLy4UETcQl kCabqLuYABVhPJ7U679uSQC+4sOeT04SXJtwKn59QCM2GopJl0aUC/aKY2s/eXh56kiN 82HK87IQbq7mqG8ARD/1T55gzmYi1RQwSGztPFfWC38VdC2D7N6UXcnmTgcyCx/c1bll DVJw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Date: Mon, 9 Apr 2018 10:12:21 -0700 Sender: tip tree robot From: tip-bot for Dave Hansen Message-ID: Cc: jgross@suse.com, peterz@infradead.org, gregkh@linuxfoundation.org, namit@vmware.com, hughd@google.com, torvalds@linux-foundation.org, tglx@linutronix.de, keescook@google.com, dan.j.williams@intel.com, arjan@linux.intel.com, jpoimboe@redhat.com, bp@alien8.de, mingo@kernel.org, aarcange@redhat.com, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, dwmw2@infradead.org, luto@kernel.org, hpa@zytor.com Reply-To: hughd@google.com, torvalds@linux-foundation.org, tglx@linutronix.de, gregkh@linuxfoundation.org, peterz@infradead.org, jgross@suse.com, namit@vmware.com, luto@kernel.org, dwmw2@infradead.org, hpa@zytor.com, arjan@linux.intel.com, keescook@google.com, dan.j.williams@intel.com, jpoimboe@redhat.com, bp@alien8.de, mingo@kernel.org, aarcange@redhat.com, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org In-Reply-To: <20180406205504.9B0F44A9@viggo.jf.intel.com> References: <20180406205504.9B0F44A9@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/mm: Undo double _PAGE_PSE clearing Git-Commit-ID: 606c7193d5fbf8ea3dafc8a9468f719fbf1d7160 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 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597289512511909608?= X-GMAIL-MSGID: =?utf-8?q?1597289512511909608?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Commit-ID: 606c7193d5fbf8ea3dafc8a9468f719fbf1d7160 Gitweb: https://git.kernel.org/tip/606c7193d5fbf8ea3dafc8a9468f719fbf1d7160 Author: Dave Hansen AuthorDate: Fri, 6 Apr 2018 13:55:04 -0700 Committer: Ingo Molnar CommitDate: Mon, 9 Apr 2018 18:27:32 +0200 x86/mm: Undo double _PAGE_PSE clearing When clearing _PAGE_PRESENT on a huge page, we need to be careful to also clear _PAGE_PSE, otherwise it might still get confused for a valid large page table entry. We do that near the spot where we *set* _PAGE_PSE. That's fine, but it's unnecessary. pgprot_large_2_4k() already did it. BTW, I also noticed that pgprot_large_2_4k() and pgprot_4k_2_large() are not symmetric. pgprot_large_2_4k() clears _PAGE_PSE (because it is aliased to _PAGE_PAT) but pgprot_4k_2_large() does not put _PAGE_PSE back. Bummer. Also, add some comments and change "promote" to "move". "Promote" seems an odd word to move when we are logically moving a bit to a lower bit position. Also add an extra line return to make it clear to which line the comment applies. Signed-off-by: Dave Hansen Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205504.9B0F44A9@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 4d369d5c04c5..d3442dfdfced 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -583,6 +583,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * up accordingly. */ old_pte = *kpte; + /* Clear PSE (aka _PAGE_PAT) and move PAT bit to correct position */ req_prot = pgprot_large_2_4k(old_prot); pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr); @@ -597,8 +598,6 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, req_prot = pgprot_clear_protnone_bits(req_prot); if (pgprot_val(req_prot) & _PAGE_PRESENT) pgprot_val(req_prot) |= _PAGE_PSE; - else - pgprot_val(req_prot) &= ~_PAGE_PSE; req_prot = canon_pgprot(req_prot); /* @@ -684,8 +683,12 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, switch (level) { case PG_LEVEL_2M: ref_prot = pmd_pgprot(*(pmd_t *)kpte); - /* clear PSE and promote PAT bit to correct position */ + /* + * Clear PSE (aka _PAGE_PAT) and move + * PAT bit to correct position. + */ ref_prot = pgprot_large_2_4k(ref_prot); + ref_pfn = pmd_pfn(*(pmd_t *)kpte); break;