From patchwork Thu Mar 19 03:56:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aneesh Kumar K V X-Patchwork-Id: 1257913 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48jY5Z0jhXz9sTT for ; Thu, 19 Mar 2020 14:57:38 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727001AbgCSD5g (ORCPT ); Wed, 18 Mar 2020 23:57:36 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:21098 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727234AbgCSD5g (ORCPT ); Wed, 18 Mar 2020 23:57:36 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02J3WfX8081581; Wed, 18 Mar 2020 23:57:19 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 2yu98tyepk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 18 Mar 2020 23:57:19 -0400 Received: from m0098413.ppops.net (m0098413.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 02J3jqia135984; Wed, 18 Mar 2020 23:57:19 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0b-001b2d01.pphosted.com with ESMTP id 2yu98tyepa-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 18 Mar 2020 23:57:19 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 02J3uwWE029795; Thu, 19 Mar 2020 03:57:18 GMT Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by ppma01wdc.us.ibm.com with ESMTP id 2yrpw6nmvq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 19 Mar 2020 03:57:18 +0000 Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02J3vHtv36372842 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 19 Mar 2020 03:57:17 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D03D7112062; Thu, 19 Mar 2020 03:57:17 +0000 (GMT) Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 28347112063; Thu, 19 Mar 2020 03:57:14 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.199.34.213]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 19 Mar 2020 03:57:13 +0000 (GMT) From: "Aneesh Kumar K.V" To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org Cc: npiggin@gmail.com, paulus@ozlabs.org, leonardo@linux.ibm.com, kirill@shutemov.name, "Aneesh Kumar K.V" , Alexey Kardashevskiy Subject: [PATCH v2 15/22] powerpc/kvm/book3s: use find_kvm_host_pte in pute_tce functions Date: Thu, 19 Mar 2020 09:26:02 +0530 Message-Id: <20200319035609.158654-16-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200319035609.158654-1-aneesh.kumar@linux.ibm.com> References: <20200319035609.158654-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.645 definitions=2020-03-18_10:2020-03-18,2020-03-18 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 clxscore=1015 adultscore=0 mlxlogscore=999 suspectscore=8 impostorscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003190013 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Current code just hold rmap lock to ensure parallel page table update is prevented. That is not sufficient. The kernel should also check whether a mmu_notifer callback was running in parallel. Cc: Alexey Kardashevskiy Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/kvm/book3s_64_vio_hv.c | 30 +++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c index ab6eeb8e753e..8a6bf12d2e88 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c @@ -438,8 +438,8 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, return H_SUCCESS; } -static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu, - unsigned long ua, unsigned long *phpa) +static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu, unsigned long mmu_seq, + unsigned long ua, unsigned long *phpa) { pte_t *ptep, pte; unsigned shift = 0; @@ -453,10 +453,17 @@ static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu, * to exit which will agains result in the below page table walk * to finish. */ - ptep = __find_linux_pte(vcpu->arch.pgdir, ua, NULL, &shift); - if (!ptep || !pte_present(*ptep)) + /* an rmap lock won't make it safe. because that just ensure hash + * page table entries are removed with rmap lock held. After that + * mmu notifier returns and we go ahead and removing ptes from Qemu page table. + */ + ptep = find_kvm_host_pte(vcpu->kvm, mmu_seq, ua, &shift); + if (!ptep) + return -ENXIO; + + pte = READ_ONCE(*ptep); + if (!pte_present(pte)) return -ENXIO; - pte = *ptep; if (!shift) shift = PAGE_SHIFT; @@ -478,10 +485,12 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, unsigned long liobn, unsigned long ioba, unsigned long tce_list, unsigned long npages) { + struct kvm *kvm = vcpu->kvm; struct kvmppc_spapr_tce_table *stt; long i, ret = H_SUCCESS; unsigned long tces, entry, ua = 0; unsigned long *rmap = NULL; + unsigned long mmu_seq; bool prereg = false; struct kvmppc_spapr_tce_iommu_table *stit; @@ -489,6 +498,12 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, if (kvm_is_radix(vcpu->kvm)) return H_TOO_HARD; + /* + * used to check for invalidations in progress + */ + mmu_seq = kvm->mmu_notifier_seq; + smp_rmb(); + stt = kvmppc_find_table(vcpu->kvm, liobn); if (!stt) return H_TOO_HARD; @@ -548,7 +563,9 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, * real page. */ lock_rmap(rmap); - if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) { + + arch_spin_lock(&kvm->mmu_lock.rlock.raw_lock); + if (kvmppc_rm_ua_to_hpa(vcpu, mmu_seq, ua, &tces)) { ret = H_TOO_HARD; goto unlock_exit; } @@ -594,6 +611,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, if (rmap) unlock_rmap(rmap); + arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock); return ret; }