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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C0920C56202 for ; Wed, 25 Nov 2020 19:48:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6148F2083E for ; Wed, 25 Nov 2020 19:48:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="V8tCVBB9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729067AbgKYTsW (ORCPT ); Wed, 25 Nov 2020 14:48:22 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:49554 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729007AbgKYTsW (ORCPT ); Wed, 25 Nov 2020 14:48:22 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0APJitnU054929; Wed, 25 Nov 2020 19:48:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=message-id : date : from : mime-version : to : cc : subject : references : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=epiqMBJ5lLDXN1oZKLWUGI5EBe3pcqP2c/wa0GUUOfc=; b=V8tCVBB9OAlZVOSR18OalnrluszF+sEyOdESr+ierhQ8blCu3jGg2JFJBRU0sfGJrdgb u6ovEIV876lB64+8W1lQiKL6isw/nEGry7mUewNbHHkTTRQPyh56MuBgOhnhJBTWGRB1 QD9lYBFz8nB9EzKqnlV4EU5lw58Z+drV0shOyHV8C857VdvnTqmng5AAjz7w4AEfM3j6 xXIdFixV0EmTvIvHQuC6hgcAkWK4OI7XccXCZ9BeEO/UaokGi2dtJyTiJWg2uY+J+J9J OUD7EK8ZbPYBR4DxaY3/0HWhnfecFR9ONPXnK3fG+x3MOAx6zz+n41cIZichiC/GLpWR rA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 351kwhb57c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 25 Nov 2020 19:48:14 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0APJixPw018399; Wed, 25 Nov 2020 19:48:14 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 351kwetgkx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 25 Nov 2020 19:48:13 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0APJmChZ024738; Wed, 25 Nov 2020 19:48:13 GMT Received: from [10.159.138.187] (/10.159.138.187) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 25 Nov 2020 11:48:11 -0800 Message-ID: <5FBEB4F9.3060008@oracle.com> Date: Wed, 25 Nov 2020 11:48:09 -0800 From: si-wei liu Organization: Oracle Corporation User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: jasowang@redhat.com, lingshan.zhu@intel.com, joao.m.martins@oracle.com, boris.ostrovsky@oracle.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v3] vhost-vdpa: fix page pinning leakage in error path (rework) References: <1604618793-4681-1-git-send-email-si-wei.liu@oracle.com> <20201125042834-mutt-send-email-mst@kernel.org> In-Reply-To: <20201125042834-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9816 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 spamscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 suspectscore=2 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011250123 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9816 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 suspectscore=2 adultscore=0 impostorscore=0 mlxscore=0 spamscore=0 phishscore=0 malwarescore=0 clxscore=1015 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011250123 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/25/2020 1:30 AM, Michael S. Tsirkin wrote: > On Thu, Nov 05, 2020 at 06:26:33PM -0500, Si-Wei Liu wrote: >> Pinned pages are not properly accounted particularly when >> mapping error occurs on IOTLB update. Clean up dangling >> pinned pages for the error path. >> >> The memory usage for bookkeeping pinned pages is reverted >> to what it was before: only one single free page is needed. >> This helps reduce the host memory demand for VM with a large >> amount of memory, or in the situation where host is running >> short of free memory. >> >> Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") >> Signed-off-by: Si-Wei Liu > > Not sure which tree this is against, I had to apply this with > minor tweaks. Pls take a look at the vhost tree and > let me know whether it looks ok to you. Thanks Michael, the commit ad89653f79f1882d55d9df76c9b2b94f008c4e27 in the vhost tree looks good. Sorry, I don't think I ever attempted to merge with linux-next when v3 was posted, although I did it for the first two submissions. I will pay attention to it next time. Thanks, -Siwei > >> --- >> Changes in v3: >> - Turn explicit last_pfn check to a WARN_ON() (Jason) >> >> Changes in v2: >> - Drop the reversion patch >> - Fix unhandled page leak towards the end of page_list >> >> drivers/vhost/vdpa.c | 80 ++++++++++++++++++++++++++++++++++++++++------------ >> 1 file changed, 62 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >> index b6d9016..5b13dfd 100644 >> --- a/drivers/vhost/vdpa.c >> +++ b/drivers/vhost/vdpa.c >> @@ -560,6 +560,8 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, >> >> if (r) >> vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1); >> + else >> + atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm); >> >> return r; >> } >> @@ -591,14 +593,16 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> unsigned long list_size = PAGE_SIZE / sizeof(struct page *); >> unsigned int gup_flags = FOLL_LONGTERM; >> unsigned long npages, cur_base, map_pfn, last_pfn = 0; >> - unsigned long locked, lock_limit, pinned, i; >> + unsigned long lock_limit, sz2pin, nchunks, i; >> u64 iova = msg->iova; >> + long pinned; >> int ret = 0; >> >> if (vhost_iotlb_itree_first(iotlb, msg->iova, >> msg->iova + msg->size - 1)) >> return -EEXIST; >> >> + /* Limit the use of memory for bookkeeping */ >> page_list = (struct page **) __get_free_page(GFP_KERNEL); >> if (!page_list) >> return -ENOMEM; >> @@ -607,52 +611,75 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> gup_flags |= FOLL_WRITE; >> >> npages = PAGE_ALIGN(msg->size + (iova & ~PAGE_MASK)) >> PAGE_SHIFT; >> - if (!npages) >> - return -EINVAL; >> + if (!npages) { >> + ret = -EINVAL; >> + goto free; >> + } >> >> mmap_read_lock(dev->mm); >> >> - locked = atomic64_add_return(npages, &dev->mm->pinned_vm); >> lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; >> - >> - if (locked > lock_limit) { >> + if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) { >> ret = -ENOMEM; >> - goto out; >> + goto unlock; >> } >> >> cur_base = msg->uaddr & PAGE_MASK; >> iova &= PAGE_MASK; >> + nchunks = 0; >> >> while (npages) { >> - pinned = min_t(unsigned long, npages, list_size); >> - ret = pin_user_pages(cur_base, pinned, >> - gup_flags, page_list, NULL); >> - if (ret != pinned) >> + sz2pin = min_t(unsigned long, npages, list_size); >> + pinned = pin_user_pages(cur_base, sz2pin, >> + gup_flags, page_list, NULL); >> + if (sz2pin != pinned) { >> + if (pinned < 0) { >> + ret = pinned; >> + } else { >> + unpin_user_pages(page_list, pinned); >> + ret = -ENOMEM; >> + } >> goto out; >> + } >> + nchunks++; >> >> if (!last_pfn) >> map_pfn = page_to_pfn(page_list[0]); >> >> - for (i = 0; i < ret; i++) { >> + for (i = 0; i < pinned; i++) { >> unsigned long this_pfn = page_to_pfn(page_list[i]); >> u64 csize; >> >> if (last_pfn && (this_pfn != last_pfn + 1)) { >> /* Pin a contiguous chunk of memory */ >> csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT; >> - if (vhost_vdpa_map(v, iova, csize, >> - map_pfn << PAGE_SHIFT, >> - msg->perm)) >> + ret = vhost_vdpa_map(v, iova, csize, >> + map_pfn << PAGE_SHIFT, >> + msg->perm); >> + if (ret) { >> + /* >> + * Unpin the pages that are left unmapped >> + * from this point on in the current >> + * page_list. The remaining outstanding >> + * ones which may stride across several >> + * chunks will be covered in the common >> + * error path subsequently. >> + */ >> + unpin_user_pages(&page_list[i], >> + pinned - i); >> goto out; >> + } >> + >> map_pfn = this_pfn; >> iova += csize; >> + nchunks = 0; >> } >> >> last_pfn = this_pfn; >> } >> >> - cur_base += ret << PAGE_SHIFT; >> - npages -= ret; >> + cur_base += pinned << PAGE_SHIFT; >> + npages -= pinned; >> } >> >> /* Pin the rest chunk */ >> @@ -660,10 +687,27 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> map_pfn << PAGE_SHIFT, msg->perm); >> out: >> if (ret) { >> + if (nchunks) { >> + unsigned long pfn; >> + >> + /* >> + * Unpin the outstanding pages which are yet to be >> + * mapped but haven't due to vdpa_map() or >> + * pin_user_pages() failure. >> + * >> + * Mapped pages are accounted in vdpa_map(), hence >> + * the corresponding unpinning will be handled by >> + * vdpa_unmap(). >> + */ >> + WARN_ON(!last_pfn); >> + for (pfn = map_pfn; pfn <= last_pfn; pfn++) >> + unpin_user_page(pfn_to_page(pfn)); >> + } >> vhost_vdpa_unmap(v, msg->iova, msg->size); >> - atomic64_sub(npages, &dev->mm->pinned_vm); >> } >> +unlock: >> mmap_read_unlock(dev->mm); >> +free: >> free_page((unsigned long)page_list); >> return ret; >> } >> -- >> 1.8.3.1