Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751653AbdFHFfh (ORCPT ); Thu, 8 Jun 2017 01:35:37 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:33658 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751444AbdFHFfg (ORCPT ); Thu, 8 Jun 2017 01:35:36 -0400 Date: Thu, 8 Jun 2017 07:35:28 +0200 From: Martin Schwidefsky To: Heiko Carstens Cc: Christian Borntraeger , David Hildenbrand , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Huth , Andreas Krebbel Subject: Re: [PATCH RFC 0/2] KVM: s390: avoid having to enable vm.alloc_pgste In-Reply-To: <20170607204756.GA3143@osiris> References: <20170529163202.13077-1-david@redhat.com> <20170601124651.3e7969ab@mschwideX1> <20170602070210.GA4221@osiris> <20170602114647.35e6d30f@mschwideX1> <2d45c9d5-2108-7408-e7cd-44b9f6d03b0f@de.ibm.com> <20170602125345.5ac9e12e@mschwideX1> <63b5c762-fbbb-b6dc-0f2d-6837dac5bb04@de.ibm.com> <20170607143440.7c86af85@mschwideX1> <20170607204756.GA3143@osiris> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 17060805-0012-0000-0000-000005477532 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17060805-0013-0000-0000-000018B66A16 Message-Id: <20170608073528.52b17428@mschwideX1> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-08_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706080101 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1818 Lines: 49 On Wed, 7 Jun 2017 22:47:56 +0200 Heiko Carstens wrote: > On Wed, Jun 07, 2017 at 02:34:40PM +0200, Martin Schwidefsky wrote: > > +#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state) \ > > +({ \ > > + struct elf64_hdr *_ehdr = (void *) ehdr; \ > > + struct elf64_phdr *_phdr = (void *) phdr; \ > > + int _rc = 0; \ > > + if (_ehdr->e_ident[EI_CLASS] == ELFCLASS64 && \ > > + _phdr->p_type == PT_S390_REQUEST_PGSTE && \ > > + !page_table_allocate_pgste && \ > > + !test_thread_flag(TIF_REQUEST_PGSTE)) { \ > > + set_thread_flag(TIF_REQUEST_PGSTE); \ > > + set_pt_regs_flag(task_pt_regs(current), \ > > + PIF_SYSCALL_RESTART); \ > > + _rc = -EAGAIN; \ > > + } \ > > + _rc; \ > > +}) > > I'm wondering if this should simply fail, if a PT_S390_REQUEST_PGSTE type > segment exists, but it is not ELFCLASS64? > It will fail later anyway on s390_enable_sie(), but... Does it matter if it fails for a 32-bit ELF file? Just makes the code more complex without benefit, no? > > diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h > > index c119d564d8f2..1201b18e817d 100644 > > --- a/arch/s390/include/asm/mmu_context.h > > +++ b/arch/s390/include/asm/mmu_context.h > > @@ -25,7 +25,8 @@ static inline int init_new_context(struct task_struct *tsk, > > mm->context.gmap_asce = 0; > > mm->context.flush_mm = 0; > > #ifdef CONFIG_PGSTE > > - mm->context.alloc_pgste = page_table_allocate_pgste; > > + mm->context.alloc_pgste = page_table_allocate_pgste || > > + test_thread_flag(TIF_REQUEST_PGSTE); > > I think the alloc_pgste flag should be inherited on fork, no? Yes, that makes it more consistent. I'll add it. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.