From patchwork Fri Jul 24 08:35:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Dufour X-Patchwork-Id: 1335474 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (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 4BCjHP3pr3z9sSn for ; Fri, 24 Jul 2020 18:37:05 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BCjHP34V5zF0Qm for ; Fri, 24 Jul 2020 18:37:05 +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=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=ldufour@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.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 4BCjFq59HSzDrPB for ; Fri, 24 Jul 2020 18:35:43 +1000 (AEST) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06O8X8dd027433; Fri, 24 Jul 2020 04:35:35 -0400 Received: from ppma05fra.de.ibm.com (6c.4a.5195.ip4.static.sl-reverse.com [149.81.74.108]) by mx0b-001b2d01.pphosted.com with ESMTP id 32fat2m9a9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 24 Jul 2020 04:35:35 -0400 Received: from pps.filterd (ppma05fra.de.ibm.com [127.0.0.1]) by ppma05fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06O8UKRc014893; Fri, 24 Jul 2020 08:35:33 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma05fra.de.ibm.com with ESMTP id 32brq83w60-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 24 Jul 2020 08:35:33 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06O8Y6ZC54985200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Jul 2020 08:34:06 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A03ACAE05A; Fri, 24 Jul 2020 08:35:30 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2D584AE04D; Fri, 24 Jul 2020 08:35:30 +0000 (GMT) Received: from pomme.tlslab.ibm.com (unknown [9.145.182.168]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 24 Jul 2020 08:35:30 +0000 (GMT) From: Laurent Dufour To: bharata@linux.ibm.com, linuxram@us.ibm.com Subject: [PATCH] KVM: PPC: Book3S HV: rework secure mem slot dropping Date: Fri, 24 Jul 2020 10:35:27 +0200 Message-Id: <20200724083527.28027-1-ldufour@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200724030337.GC1082478@in.ibm.com> References: <20200724030337.GC1082478@in.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-24_02:2020-07-24, 2020-07-24 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=2 spamscore=0 phishscore=0 adultscore=0 clxscore=1015 priorityscore=1501 mlxscore=0 lowpriorityscore=0 impostorscore=0 malwarescore=0 mlxlogscore=763 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007240059 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: cclaudio@linux.ibm.com, kvm-ppc@vger.kernel.org, sathnaga@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, sukadev@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, bauerman@linux.ibm.com, david@gibson.dropbear.id.au Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When a secure memslot is dropped, all the pages backed in the secure device (aka really backed by secure memory by the Ultravisor) should be paged out to a normal page. Previously, this was achieved by triggering the page fault mechanism which is calling kvmppc_svm_page_out() on each pages. This can't work when hot unplugging a memory slot because the memory slot is flagged as invalid and gfn_to_pfn() is then not trying to access the page, so the page fault mechanism is not triggered. Since the final goal is to make a call to kvmppc_svm_page_out() it seems simpler to call directly instead of triggering such a mechanism. This way kvmppc_uvmem_drop_pages() can be called even when hot unplugging a memslot. Since kvmppc_uvmem_drop_pages() is already holding kvm->arch.uvmem_lock, the call to __kvmppc_svm_page_out() is made. As __kvmppc_svm_page_out needs the vma pointer to migrate the pages, the VMA is fetched in a lazy way, to not trigger find_vma() all the time. In addition, the mmap_sem is held in read mode during that time, not in write mode since the virual memory layout is not impacted, and kvm->arch.uvmem_lock prevents concurrent operation on the secure device. Cc: Ram Pai Cc: Bharata B Rao Cc: Paul Mackerras Signed-off-by: Ram Pai [modified the changelog description] Signed-off-by: Laurent Dufour [modified check on the VMA in kvmppc_uvmem_drop_pages] Reviewed-by: Bharata B Rao --- arch/powerpc/kvm/book3s_hv_uvmem.c | 53 ++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 17 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index c772e921f769..5dd3e9acdcab 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -632,35 +632,54 @@ static inline int kvmppc_svm_page_out(struct vm_area_struct *vma, * fault on them, do fault time migration to replace the device PTEs in * QEMU page table with normal PTEs from newly allocated pages. */ -void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free, +void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *slot, struct kvm *kvm, bool skip_page_out) { int i; struct kvmppc_uvmem_page_pvt *pvt; - unsigned long pfn, uvmem_pfn; - unsigned long gfn = free->base_gfn; + struct page *uvmem_page; + struct vm_area_struct *vma = NULL; + unsigned long uvmem_pfn, gfn; + unsigned long addr, end; + + mmap_read_lock(kvm->mm); + + addr = slot->userspace_addr; + end = addr + (slot->npages * PAGE_SIZE); - for (i = free->npages; i; --i, ++gfn) { - struct page *uvmem_page; + gfn = slot->base_gfn; + for (i = slot->npages; i; --i, ++gfn, addr += PAGE_SIZE) { + + /* Fetch the VMA if addr is not in the latest fetched one */ + if (!vma || addr >= vma->vm_end) { + vma = find_vma_intersection(kvm->mm, addr, addr+1); + if (!vma) { + pr_err("Can't find VMA for gfn:0x%lx\n", gfn); + break; + } + } mutex_lock(&kvm->arch.uvmem_lock); - if (!kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) { + + if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) { + uvmem_page = pfn_to_page(uvmem_pfn); + pvt = uvmem_page->zone_device_data; + pvt->skip_page_out = skip_page_out; + pvt->remove_gfn = true; + + if (__kvmppc_svm_page_out(vma, addr, addr + PAGE_SIZE, + PAGE_SHIFT, kvm, pvt->gpa)) + pr_err("Can't page out gpa:0x%lx addr:0x%lx\n", + pvt->gpa, addr); + } else { + /* Remove the shared flag if any */ kvmppc_gfn_remove(gfn, kvm); - mutex_unlock(&kvm->arch.uvmem_lock); - continue; } - uvmem_page = pfn_to_page(uvmem_pfn); - pvt = uvmem_page->zone_device_data; - pvt->skip_page_out = skip_page_out; - pvt->remove_gfn = true; mutex_unlock(&kvm->arch.uvmem_lock); - - pfn = gfn_to_pfn(kvm, gfn); - if (is_error_noslot_pfn(pfn)) - continue; - kvm_release_pfn_clean(pfn); } + + mmap_read_unlock(kvm->mm); } unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)