Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755307AbaJCVui (ORCPT ); Fri, 3 Oct 2014 17:50:38 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45634 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756240AbaJCVpY (ORCPT ); Fri, 3 Oct 2014 17:45:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christian Borntraeger , Dominik Dingel Subject: [PATCH 3.16 210/357] KVM: s390/mm: try a cow on read only pages for key ops Date: Fri, 3 Oct 2014 14:29:56 -0700 Message-Id: <20141003212939.841311506@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003212933.458851516@linuxfoundation.org> References: <20141003212933.458851516@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Borntraeger commit ab3f285f227fec62868037e9b1b1fd18294a83b8 upstream. The PFMF instruction handler blindly wrote the storage key even if the page was mapped R/O in the host. Lets try a COW before continuing and bail out in case of errors. Signed-off-by: Christian Borntraeger Reviewed-by: Dominik Dingel Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/pgtable.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -986,11 +986,21 @@ int set_guest_storage_key(struct mm_stru pte_t *ptep; down_read(&mm->mmap_sem); +retry: ptep = get_locked_pte(current->mm, addr, &ptl); if (unlikely(!ptep)) { up_read(&mm->mmap_sem); return -EFAULT; } + if (!(pte_val(*ptep) & _PAGE_INVALID) && + (pte_val(*ptep) & _PAGE_PROTECT)) { + pte_unmap_unlock(*ptep, ptl); + if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) { + up_read(&mm->mmap_sem); + return -EFAULT; + } + goto retry; + } new = old = pgste_get_lock(ptep); pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT | -- 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/