From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24227C43460 for ; Fri, 16 Apr 2021 15:41:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C1E6613B4 for ; Fri, 16 Apr 2021 15:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236712AbhDPPmT (ORCPT ); Fri, 16 Apr 2021 11:42:19 -0400 Received: from mga17.intel.com ([192.55.52.151]:10800 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343992AbhDPPmL (ORCPT ); Fri, 16 Apr 2021 11:42:11 -0400 IronPort-SDR: wfem44kkoBDDVcbXMsVSG37pJir2Mo55HGtqbltnwwhHGatu/HRpw7VeaD4HppdxlhYfhaxR0H 4eVLQDpBwSHQ== X-IronPort-AV: E=McAfee;i="6200,9189,9956"; a="175163938" X-IronPort-AV: E=Sophos;i="5.82,226,1613462400"; d="scan'208";a="175163938" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2021 08:41:43 -0700 IronPort-SDR: BiatwMA0y8qUcIW7/n3v5VFpxjtDSkQkoZb1k+sB1Z4cLkxVSZkRIORtiu9iZm6VdBUjhLkGV4 eMT6uG8NXbTQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,226,1613462400"; d="scan'208";a="422038787" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga007.jf.intel.com with ESMTP; 16 Apr 2021 08:41:38 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 41BE135E; Fri, 16 Apr 2021 18:41:50 +0300 (EEST) From: "Kirill A. Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Sean Christopherson , Jim Mattson Cc: David Rientjes , "Edgecombe, Rick P" , "Kleen, Andi" , "Yamahata, Isaku" , Erdem Aktas , Steve Rutherford , Peter Gonda , David Hildenbrand , x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [RFCv2 11/13] mm: Replace hwpoison entry with present PTE if page got unpoisoned Date: Fri, 16 Apr 2021 18:41:04 +0300 Message-Id: <20210416154106.23721-12-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416154106.23721-1-kirill.shutemov@linux.intel.com> References: <20210416154106.23721-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org If the page got unpoisoned we can replace hwpoison entry with a present PTE on page fault instead of delivering SIGBUS. Signed-off-by: Kirill A. Shutemov --- mm/memory.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index b15b0c582186..56f93e8e98f9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3280,7 +3280,43 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) vmf->page = device_private_entry_to_page(entry); ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); } else if (is_hwpoison_entry(entry)) { - ret = VM_FAULT_HWPOISON; + page = hwpoison_entry_to_page(entry); + + locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); + if (!locked) { + ret = VM_FAULT_RETRY; + goto out; + } + + vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, + vmf->address, &vmf->ptl); + + if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { + ret = 0; + } else if (PageHWPoison(page)) { + ret = VM_FAULT_HWPOISON; + } else { + /* + * The page is unpoisoned. Replace hwpoison + * entry with a present PTE. + */ + + inc_mm_counter(vma->vm_mm, mm_counter(page)); + pte = mk_pte(page, vma->vm_page_prot); + + if (PageAnon(page)) { + page_add_anon_rmap(page, vma, + vmf->address, false); + } else { + page_add_file_rmap(page, false); + } + + set_pte_at(vma->vm_mm, vmf->address, + vmf->pte, pte); + } + + pte_unmap_unlock(vmf->pte, vmf->ptl); + unlock_page(page); } else { print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); ret = VM_FAULT_SIGBUS; -- 2.26.3