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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 09C9EC4360C for ; Thu, 3 Oct 2019 01:36:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AB88521D81 for ; Thu, 3 Oct 2019 01:36:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB88521D81 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 572FB6B0270; Wed, 2 Oct 2019 21:36:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 523246B0271; Wed, 2 Oct 2019 21:36:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 412426B0272; Wed, 2 Oct 2019 21:36:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0037.hostedemail.com [216.40.44.37]) by kanga.kvack.org (Postfix) with ESMTP id 1FEB36B0270 for ; Wed, 2 Oct 2019 21:36:16 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id C3253483C for ; Thu, 3 Oct 2019 01:36:15 +0000 (UTC) X-FDA: 76000757910.15.thing15_53b7c3d6a254f X-HE-Tag: thing15_53b7c3d6a254f X-Filterd-Recvd-Size: 12753 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 3 Oct 2019 01:36:15 +0000 (UTC) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x931WW4c021212; Wed, 2 Oct 2019 21:35:53 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vd3wfmxrw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Oct 2019 21:35:53 -0400 Received: from m0098393.ppops.net (m0098393.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x931ZqlQ027954; Wed, 2 Oct 2019 21:35:52 -0400 Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com [169.47.144.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vd3wfmxrj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Oct 2019 21:35:52 -0400 Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1]) by ppma04wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x931U5BN025461; Thu, 3 Oct 2019 01:35:51 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma04wdc.us.ibm.com with ESMTP id 2v9y588efe-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 03 Oct 2019 01:35:51 +0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x931ZnV461800724 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 3 Oct 2019 01:35:49 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 435947805F; Thu, 3 Oct 2019 01:35:49 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BF7CB78060; Thu, 3 Oct 2019 01:35:36 +0000 (GMT) Received: from LeoBras.ibmuc.com (unknown [9.85.174.224]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Thu, 3 Oct 2019 01:35:36 +0000 (GMT) From: Leonardo Bras To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: Leonardo Bras , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Arnd Bergmann , "Aneesh Kumar K.V" , Christophe Leroy , Nicholas Piggin , Andrew Morton , Mahesh Salgaonkar , Reza Arbab , Santosh Sivaraj , Balbir Singh , Thomas Gleixner , Greg Kroah-Hartman , Mike Rapoport , Allison Randal , Jason Gunthorpe , Dan Williams , Vlastimil Babka , Christoph Lameter , Logan Gunthorpe , Andrey Ryabinin , Alexey Dobriyan , Souptick Joarder , Mathieu Desnoyers , Ralph Campbell , Jesper Dangaard Brouer , Jann Horn , Davidlohr Bueso , "Peter Zijlstra (Intel)" , Ingo Molnar , Christian Brauner , Michal Hocko , Elena Reshetova , Roman Gushchin , Andrea Arcangeli , Al Viro , "Dmitry V. Levin" , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Song Liu , Bartlomiej Zolnierkiewicz , Ira Weiny , "Kirill A. Shutemov" , John Hubbard , Keith Busch Subject: [PATCH v5 09/11] powerpc/kvm/book3s_64: Applies counting method to monitor lockless pgtbl walks Date: Wed, 2 Oct 2019 22:33:23 -0300 Message-Id: <20191003013325.2614-10-leonardo@linux.ibm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191003013325.2614-1-leonardo@linux.ibm.com> References: <20191003013325.2614-1-leonardo@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-10-03_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=459 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910030012 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Applies the counting-based method for monitoring all book3s_64-related functions that do lockless pagetable walks. Adds comments explaining that some lockless pagetable walks don't need protection due to guest pgd not being a target of THP collapse/split, or due to being called from Realmode + MSR_EE =3D 0. Given that some of these functions always are called in realmode, we use __{begin,end}_lockless_pgtbl_walk so we can decide when to disable interrupts. local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_wal= k, so there is no need to repeat it here. Variable that saves the irq mask was renamed from flags to irq_mask so it doesn't lose meaning now it's not directly passed to local_irq_* function= s. There are also a function that uses local_irq_{en,dis}able, so the return value of begin_lockless_pgtbl_walk() is ignored and we pass IRQS_ENABLED = to end_lockless_pgtbl_walk() to mimic the effect of local_irq_enable(). Signed-off-by: Leonardo Bras --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 6 ++--- arch/powerpc/kvm/book3s_64_mmu_radix.c | 34 +++++++++++++++++++++++--- arch/powerpc/kvm/book3s_64_vio_hv.c | 7 +++++- 3 files changed, 40 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3= s_64_mmu_hv.c index 9a75f0e1933b..d8f374c979f5 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -615,12 +615,12 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run= , struct kvm_vcpu *vcpu, /* if the guest wants write access, see if that is OK */ if (!writing && hpte_is_writable(r)) { pte_t *ptep, pte; - unsigned long flags; + unsigned long irq_mask; /* * We need to protect against page table destruction * hugepage split and collapse. */ - local_irq_save(flags); + irq_mask =3D begin_lockless_pgtbl_walk(kvm->mm); ptep =3D find_current_mm_pte(current->mm->pgd, hva, NULL, NULL); if (ptep) { @@ -628,7 +628,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, = struct kvm_vcpu *vcpu, if (__pte_write(pte)) write_ok =3D 1; } - local_irq_restore(flags); + end_lockless_pgtbl_walk(kvm->mm, irq_mask); } } =20 diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/bo= ok3s_64_mmu_radix.c index 2d415c36a61d..8ba9742e2fc8 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -813,20 +813,20 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu = *vcpu, * Read the PTE from the process' radix tree and use that * so we get the shift and attribute bits. */ - local_irq_disable(); + begin_lockless_pgtbl_walk(kvm->mm); ptep =3D __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift); /* * If the PTE disappeared temporarily due to a THP * collapse, just return and let the guest try again. */ if (!ptep) { - local_irq_enable(); + end_lockless_pgtbl_walk(kvm->mm, IRQS_ENABLED); if (page) put_page(page); return RESUME_GUEST; } pte =3D *ptep; - local_irq_enable(); + end_lockless_pgtbl_walk(kvm->mm, IRQS_ENABLED); =20 /* If we're logging dirty pages, always map single pages */ large_enable =3D !(memslot->flags & KVM_MEM_LOG_DIRTY_PAGES); @@ -972,10 +972,16 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_mem= ory_slot *memslot, unsigned long gpa =3D gfn << PAGE_SHIFT; unsigned int shift; =20 + /* + * We are walking the secondary (partition-scoped) page table here. + * We can do this without disabling irq because the Linux MM + * subsystem doesn't do THP splits and collapses on this tree. + */ ptep =3D __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep)) kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot, kvm->arch.lpid); + return 0; =09 } =20 @@ -989,6 +995,11 @@ int kvm_age_radix(struct kvm *kvm, struct kvm_memory= _slot *memslot, int ref =3D 0; unsigned long old, *rmapp; =20 + /* + * We are walking the secondary (partition-scoped) page table here. + * We can do this without disabling irq because the Linux MM + * subsystem doesn't do THP splits and collapses on this tree. + */ ptep =3D __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) { old =3D kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0, @@ -1013,6 +1024,11 @@ int kvm_test_age_radix(struct kvm *kvm, struct kvm= _memory_slot *memslot, unsigned int shift; int ref =3D 0; =20 + /* + * We are walking the secondary (partition-scoped) page table here. + * We can do this without disabling irq because the Linux MM + * subsystem doesn't do THP splits and collapses on this tree. + */ ptep =3D __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_young(*ptep)) ref =3D 1; @@ -1030,6 +1046,11 @@ static int kvm_radix_test_clear_dirty(struct kvm *= kvm, int ret =3D 0; unsigned long old, *rmapp; =20 + /* + * We are walking the secondary (partition-scoped) page table here. + * We can do this without disabling irq because the Linux MM + * subsystem doesn't do THP splits and collapses on this tree. + */ ptep =3D __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) { ret =3D 1; @@ -1046,6 +1067,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *k= vm, 1UL << shift); spin_unlock(&kvm->mmu_lock); } + return ret; } =20 @@ -1085,6 +1107,12 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm, gpa =3D memslot->base_gfn << PAGE_SHIFT; spin_lock(&kvm->mmu_lock); for (n =3D memslot->npages; n; --n) { + /* + * We are walking the secondary (partition-scoped) page table + * here. + * We can do this without disabling irq because the Linux MM + * subsystem doesn't do THP splits and collapses on this tree. + */ ptep =3D __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift); if (ptep && pte_present(*ptep)) kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot, diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3= s_64_vio_hv.c index ab6eeb8e753e..0091c3d0ce89 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c @@ -441,6 +441,7 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsig= ned long liobn, static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu, unsigned long ua, unsigned long *phpa) { + struct kvm *kvm =3D vcpu->kvm; pte_t *ptep, pte; unsigned shift =3D 0; =20 @@ -453,10 +454,14 @@ static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vc= pu, * to exit which will agains result in the below page table walk * to finish. */ + __begin_lockless_pgtbl_walk(kvm->mm, false); ptep =3D __find_linux_pte(vcpu->arch.pgdir, ua, NULL, &shift); - if (!ptep || !pte_present(*ptep)) + if (!ptep || !pte_present(*ptep)) { + __end_lockless_pgtbl_walk(kvm->mm, 0, false); return -ENXIO; + } pte =3D *ptep; + __end_lockless_pgtbl_walk(kvm->mm, 0, false); =20 if (!shift) shift =3D PAGE_SHIFT; --=20 2.20.1