From patchwork Fri Jul 17 08:00:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ram Pai X-Patchwork-Id: 1330902 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4B7P2R64CRz9sTN for ; Fri, 17 Jul 2020 18:10:55 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=us.ibm.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4B7P2R0tVszDrD1 for ; Fri, 17 Jul 2020 18:10:55 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=us.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=linuxram@us.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=us.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4B7NqB24zCzDrLw for ; Fri, 17 Jul 2020 18:01:09 +1000 (AEST) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06H7WgxR020794; Fri, 17 Jul 2020 04:01:01 -0400 Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0b-001b2d01.pphosted.com with ESMTP id 32ax78p5jf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Jul 2020 04:01:01 -0400 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06H7fhMa025998; Fri, 17 Jul 2020 08:00:59 GMT Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by ppma06ams.nl.ibm.com with ESMTP id 3274pgx8m4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 Jul 2020 08:00:59 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06H80uxX13566458 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Jul 2020 08:00:56 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B28E2A406E; Fri, 17 Jul 2020 08:00:55 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9E12EA406D; Fri, 17 Jul 2020 08:00:52 +0000 (GMT) Received: from oc0525413822.ibm.com (unknown [9.163.39.1]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 17 Jul 2020 08:00:52 +0000 (GMT) From: Ram Pai To: kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [v4 4/5] KVM: PPC: Book3S HV: retry page migration before erroring-out Date: Fri, 17 Jul 2020 01:00:26 -0700 Message-Id: <1594972827-13928-5-git-send-email-linuxram@us.ibm.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1594972827-13928-1-git-send-email-linuxram@us.ibm.com> References: <1594972827-13928-1-git-send-email-linuxram@us.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-17_04:2020-07-16, 2020-07-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 spamscore=0 priorityscore=1501 mlxscore=0 mlxlogscore=999 phishscore=0 lowpriorityscore=0 clxscore=1015 malwarescore=0 suspectscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007170054 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ldufour@linux.ibm.com, linuxram@us.ibm.com, cclaudio@linux.ibm.com, bharata@linux.ibm.com, sathnaga@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, sukadev@linux.vnet.ibm.com, bauerman@linux.ibm.com, david@gibson.dropbear.id.au Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" The page requested for page-in; sometimes, can have transient references, and hence cannot migrate immediately. Retry a few times before returning error. The same is true for non-migrated pages that are migrated in H_SVM_INIT_DONE hanlder. Retry a few times before returning error. H_SVM_PAGE_IN interface is enhanced to return H_BUSY if the page is not in a migratable state. Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Bharata B Rao Cc: Aneesh Kumar K.V Cc: Sukadev Bhattiprolu Cc: Laurent Dufour Cc: Thiago Jung Bauermann Cc: David Gibson Cc: Claudio Carvalho Cc: kvm-ppc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Ram Pai --- Documentation/powerpc/ultravisor.rst | 1 + arch/powerpc/kvm/book3s_hv_uvmem.c | 106 ++++++++++++++++++++++++----------- 2 files changed, 74 insertions(+), 33 deletions(-) diff --git a/Documentation/powerpc/ultravisor.rst b/Documentation/powerpc/ultravisor.rst index ba6b1bf..fe533ad 100644 --- a/Documentation/powerpc/ultravisor.rst +++ b/Documentation/powerpc/ultravisor.rst @@ -1035,6 +1035,7 @@ Return values * H_PARAMETER if ``guest_pa`` is invalid. * H_P2 if ``flags`` is invalid. * H_P3 if ``order`` of page is invalid. + * H_BUSY if ``page`` is not in a state to pagein Description ~~~~~~~~~~~ diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index 3274663..a206984 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -672,7 +672,7 @@ static int kvmppc_svm_migrate_page(struct vm_area_struct *vma, return ret; if (!(*mig.src & MIGRATE_PFN_MIGRATE)) { - ret = -1; + ret = -2; goto out_finalize; } @@ -700,43 +700,73 @@ static int kvmppc_svm_migrate_page(struct vm_area_struct *vma, return ret; } -int kvmppc_uv_migrate_mem_slot(struct kvm *kvm, - const struct kvm_memory_slot *memslot) +/* + * return 1, if some page migration failed because of transient error, + * while the remaining pages migrated successfully. + * The caller can use this as a hint to retry. + * + * return 0 otherwise. *ret indicates the success status + * of this call. + */ +static bool __kvmppc_uv_migrate_mem_slot(struct kvm *kvm, + const struct kvm_memory_slot *memslot, int *ret) { unsigned long gfn = memslot->base_gfn; struct vm_area_struct *vma; unsigned long start, end; - int ret = 0; + bool retry = false; + *ret = 0; while (kvmppc_next_nontransitioned_gfn(memslot, kvm, &gfn)) { mmap_read_lock(kvm->mm); start = gfn_to_hva(kvm, gfn); if (kvm_is_error_hva(start)) { - ret = H_STATE; + *ret = H_STATE; goto next; } end = start + (1UL << PAGE_SHIFT); vma = find_vma_intersection(kvm->mm, start, end); if (!vma || vma->vm_start > start || vma->vm_end < end) { - ret = H_STATE; + *ret = H_STATE; goto next; } mutex_lock(&kvm->arch.uvmem_lock); - ret = kvmppc_svm_migrate_page(vma, start, end, + *ret = kvmppc_svm_migrate_page(vma, start, end, (gfn << PAGE_SHIFT), kvm, PAGE_SHIFT, false); mutex_unlock(&kvm->arch.uvmem_lock); - if (ret) - ret = H_STATE; next: mmap_read_unlock(kvm->mm); + if (*ret == -2) { + retry = true; + continue; + } - if (ret) - break; + if (*ret) + return false; } + return retry; +} + +#define REPEAT_COUNT 10 + +int kvmppc_uv_migrate_mem_slot(struct kvm *kvm, + const struct kvm_memory_slot *memslot) +{ + int ret = 0, repeat_count = REPEAT_COUNT; + + /* + * try migration of pages in the memslot 'repeat_count' number of + * times, provided each time migration fails because of transient + * errors only. + */ + while (__kvmppc_uv_migrate_mem_slot(kvm, memslot, &ret) && + repeat_count--) + ; + return ret; } @@ -812,7 +842,7 @@ unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa, struct vm_area_struct *vma; int srcu_idx; unsigned long gfn = gpa >> page_shift; - int ret; + int ret, repeat_count = REPEAT_COUNT; if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START)) return H_UNSUPPORTED; @@ -826,34 +856,44 @@ unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa, if (flags & H_PAGE_IN_SHARED) return kvmppc_share_page(kvm, gpa, page_shift); - ret = H_PARAMETER; srcu_idx = srcu_read_lock(&kvm->srcu); - mmap_read_lock(kvm->mm); - start = gfn_to_hva(kvm, gfn); - if (kvm_is_error_hva(start)) - goto out; - - mutex_lock(&kvm->arch.uvmem_lock); /* Fail the page-in request of an already paged-in page */ - if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL)) - goto out_unlock; + mutex_lock(&kvm->arch.uvmem_lock); + ret = kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL); + mutex_unlock(&kvm->arch.uvmem_lock); + if (ret) { + srcu_read_unlock(&kvm->srcu, srcu_idx); + return H_PARAMETER; + } - end = start + (1UL << page_shift); - vma = find_vma_intersection(kvm->mm, start, end); - if (!vma || vma->vm_start > start || vma->vm_end < end) - goto out_unlock; + do { + ret = H_PARAMETER; + mmap_read_lock(kvm->mm); - if (kvmppc_svm_migrate_page(vma, start, end, gpa, kvm, page_shift, - true)) - goto out_unlock; + start = gfn_to_hva(kvm, gfn); + if (kvm_is_error_hva(start)) { + mmap_read_unlock(kvm->mm); + break; + } - ret = H_SUCCESS; + end = start + (1UL << page_shift); + vma = find_vma_intersection(kvm->mm, start, end); + if (!vma || vma->vm_start > start || vma->vm_end < end) { + mmap_read_unlock(kvm->mm); + break; + } + + mutex_lock(&kvm->arch.uvmem_lock); + ret = kvmppc_svm_migrate_page(vma, start, end, gpa, kvm, page_shift, true); + mutex_unlock(&kvm->arch.uvmem_lock); + + mmap_read_unlock(kvm->mm); + } while (ret == -2 && repeat_count--); + + if (ret == -2) + ret = H_BUSY; -out_unlock: - mutex_unlock(&kvm->arch.uvmem_lock); -out: - mmap_read_unlock(kvm->mm); srcu_read_unlock(&kvm->srcu, srcu_idx); return ret; }