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Thu, 23 Jul 2020 06:13:47 +0000 (GMT) Received: from in.ibm.com (unknown [9.85.75.152]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 23 Jul 2020 06:13:46 +0000 (GMT) Date: Thu, 23 Jul 2020 11:43:44 +0530 From: Bharata B Rao To: Ram Pai Subject: Re: [v4 4/5] KVM: PPC: Book3S HV: retry page migration before erroring-out Message-ID: <20200723061344.GB1082478@in.ibm.com> References: <1594972827-13928-1-git-send-email-linuxram@us.ibm.com> <1594972827-13928-5-git-send-email-linuxram@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1594972827-13928-5-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=2020-07-23_01:2020-07-22, 2020-07-23 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=503 suspectscore=1 mlxscore=0 lowpriorityscore=0 bulkscore=0 clxscore=1015 adultscore=0 malwarescore=0 spamscore=0 phishscore=0 priorityscore=1501 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007230048 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: , Reply-To: bharata@linux.ibm.com Cc: ldufour@linux.ibm.com, cclaudio@linux.ibm.com, kvm-ppc@vger.kernel.org, sathnaga@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, sukadev@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, bauerman@linux.ibm.com, david@gibson.dropbear.id.au Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Jul 17, 2020 at 01:00:26AM -0700, Ram Pai wrote: > @@ -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); Same comment as for the prev patch. I don't think you can release the lock here. > + 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; > } > -- > 1.8.3.1