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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 B089BC10DCE for ; Wed, 18 Mar 2020 12:14:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6047920724 for ; Wed, 18 Mar 2020 12:14:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Pz2QJyhK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6047920724 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49836 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEXaR-0001BM-I0 for qemu-devel@archiver.kernel.org; Wed, 18 Mar 2020 08:14:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37505) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEXZk-0000jx-2A for qemu-devel@nongnu.org; Wed, 18 Mar 2020 08:13:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEXZh-0002cD-Lp for qemu-devel@nongnu.org; Wed, 18 Mar 2020 08:13:31 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:46320) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEXZh-0002V1-FI for qemu-devel@nongnu.org; Wed, 18 Mar 2020 08:13:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584533608; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zTxXAON9YcXG0Y2z3wfR3Qe+dtfMDziTWi93aKzl7Js=; b=Pz2QJyhKQWYqZ88fVs5vJZy19JiV5+4pj7DDRsczvrE6IRM0Kf43AnP5HhGa/raQf4Kfqn iOARDP+Ea29IZAFpKvjYFiQFZJRGEwVkb8My1ulFdC+Tvi2pQdpWoMlCN/A6oltRhELoSh tr3V4jdXEfnwhbs2ZldlugxM+Jp5PcE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-292-dj3Ev-L5NYiCYjTjCsp-wQ-1; Wed, 18 Mar 2020 08:13:26 -0400 X-MC-Unique: dj3Ev-L5NYiCYjTjCsp-wQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9C938107ACC9; Wed, 18 Mar 2020 12:13:23 +0000 (UTC) Received: from work-vm (ovpn-115-3.ams2.redhat.com [10.36.115.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 217585D9C5; Wed, 18 Mar 2020 12:13:15 +0000 (UTC) Date: Wed, 18 Mar 2020 12:13:12 +0000 From: "Dr. David Alan Gilbert" To: Kirti Wankhede Subject: Re: [PATCH v13 Kernel 4/7] vfio iommu: Implementation of ioctl to for dirty pages tracking. Message-ID: <20200318121312.GI2850@work-vm> References: <1584035607-23166-1-git-send-email-kwankhede@nvidia.com> <1584035607-23166-5-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1584035607-23166-5-git-send-email-kwankhede@nvidia.com> User-Agent: Mutt/1.13.3 (2020-01-12) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zhengxiao.zx@alibaba-inc.com, kevin.tian@intel.com, yi.l.liu@intel.com, cjia@nvidia.com, kvm@vger.kernel.org, eskultet@redhat.com, ziye.yang@intel.com, cohuck@redhat.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, alex.williamson@redhat.com, eauger@redhat.com, felipe@nutanix.com, jonathan.davies@nutanix.com, yan.y.zhao@intel.com, changpeng.liu@intel.com, Ken.Xue@amd.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Kirti Wankhede (kwankhede@nvidia.com) wrote: > VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: > - Start pinned and unpinned pages tracking while migration is active > - Stop pinned and unpinned dirty pages tracking. This is also used to > stop dirty pages tracking if migration failed or cancelled. > - Get dirty pages bitmap. This ioctl returns bitmap of dirty pages, its > user space application responsibility to copy content of dirty pages > from source to destination during migration. > > To prevent DoS attack, memory for bitmap is allocated per vfio_dma > structure. Bitmap size is calculated considering smallest supported page > size. Bitmap is allocated when dirty logging is enabled for those > vfio_dmas whose vpfn list is not empty or whole range is mapped, in > case of pass-through device. > > Bitmap is populated for already pinned pages when bitmap is allocated for > a vfio_dma with the smallest supported page size. Update bitmap from > pinning and unpinning functions. When user application queries bitmap, > check if requested page size is same as page size used to populated > bitmap. If it is equal, copy bitmap, but if not equal, return error. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > drivers/vfio/vfio_iommu_type1.c | 243 +++++++++++++++++++++++++++++++++++++++- > 1 file changed, 237 insertions(+), 6 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index d386461e5d11..435e84269a28 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -70,6 +70,7 @@ struct vfio_iommu { > unsigned int dma_avail; > bool v2; > bool nesting; > + bool dirty_page_tracking; > }; > > struct vfio_domain { > @@ -90,6 +91,7 @@ struct vfio_dma { > bool lock_cap; /* capable(CAP_IPC_LOCK) */ > struct task_struct *task; > struct rb_root pfn_list; /* Ex-user pinned pfn list */ > + unsigned long *bitmap; > }; > > struct vfio_group { > @@ -125,6 +127,7 @@ struct vfio_regions { > (!list_empty(&iommu->domain_list)) > > static int put_pfn(unsigned long pfn, int prot); > +static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu); > > /* > * This code handles mapping and unmapping of user data buffers > @@ -174,6 +177,76 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) > rb_erase(&old->node, &iommu->dma_list); > } > > +static inline unsigned long dirty_bitmap_bytes(unsigned int npages) > +{ > + if (!npages) > + return 0; > + > + return ALIGN(npages, BITS_PER_LONG) / sizeof(unsigned long); > +} > + > +static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, unsigned long pgsize) > +{ > + if (!RB_EMPTY_ROOT(&dma->pfn_list) || dma->iommu_mapped) { > + unsigned long npages = dma->size / pgsize; > + > + dma->bitmap = kvzalloc(dirty_bitmap_bytes(npages), GFP_KERNEL); > + if (!dma->bitmap) > + return -ENOMEM; > + } > + return 0; > +} > + > +static int vfio_dma_all_bitmap_alloc(struct vfio_iommu *iommu, > + unsigned long pgsize) > +{ > + struct rb_node *n = rb_first(&iommu->dma_list); > + int ret; > + > + for (; n; n = rb_next(n)) { > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > + struct rb_node *n; > + > + ret = vfio_dma_bitmap_alloc(dma, pgsize); > + if (ret) { > + struct rb_node *p = rb_prev(n); > + > + for (; p; p = rb_prev(p)) { > + struct vfio_dma *dma = rb_entry(n, > + struct vfio_dma, node); > + > + kfree(dma->bitmap); > + dma->bitmap = NULL; > + } > + return ret; > + } > + > + if (!dma->bitmap) > + continue; > + > + for (n = rb_first(&dma->pfn_list); n; n = rb_next(n)) { > + struct vfio_pfn *vpfn = rb_entry(n, struct vfio_pfn, > + node); > + > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) / pgsize, 1); > + } > + } > + return 0; > +} > + > +static void vfio_dma_all_bitmap_free(struct vfio_iommu *iommu) > +{ > + struct rb_node *n = rb_first(&iommu->dma_list); > + > + for (; n; n = rb_next(n)) { > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > + > + kfree(dma->bitmap); > + dma->bitmap = NULL; > + } > +} > + > /* > * Helper Functions for host iova-pfn list > */ > @@ -254,12 +327,16 @@ static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma, > return vpfn; > } > > -static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn) > +static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn, > + bool do_tracking, unsigned long pgsize) > { > int ret = 0; > > vpfn->ref_count--; > if (!vpfn->ref_count) { > + if (do_tracking && dma->bitmap) > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) / pgsize, 1); > ret = put_pfn(vpfn->pfn, dma->prot); > vfio_remove_from_pfn_list(dma, vpfn); > } > @@ -484,7 +561,8 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr, > } > > static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova, > - bool do_accounting) > + bool do_accounting, bool do_tracking, > + unsigned long pgsize) > { > int unlocked; > struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova); > @@ -492,7 +570,7 @@ static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova, > if (!vpfn) > return 0; > > - unlocked = vfio_iova_put_vfio_pfn(dma, vpfn); > + unlocked = vfio_iova_put_vfio_pfn(dma, vpfn, do_tracking, pgsize); > > if (do_accounting) > vfio_lock_acct(dma, -unlocked, true); > @@ -563,9 +641,26 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > > ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]); > if (ret) { > - vfio_unpin_page_external(dma, iova, do_accounting); > + vfio_unpin_page_external(dma, iova, do_accounting, > + false, 0); > goto pin_unwind; > } > + > + if (iommu->dirty_page_tracking) { > + unsigned long pgshift = > + __ffs(vfio_pgsize_bitmap(iommu)); > + > + if (!dma->bitmap) { > + ret = vfio_dma_bitmap_alloc(dma, 1 << pgshift); > + if (ret) { > + vfio_unpin_page_external(dma, iova, > + do_accounting, false, 0); > + goto pin_unwind; > + } > + } > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) >> pgshift, 1); > + } > } > > ret = i; > @@ -578,7 +673,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > > iova = user_pfn[j] << PAGE_SHIFT; > dma = vfio_find_dma(iommu, iova, PAGE_SIZE); > - vfio_unpin_page_external(dma, iova, do_accounting); > + vfio_unpin_page_external(dma, iova, do_accounting, false, 0); > phys_pfn[j] = 0; > } > pin_done: > @@ -612,7 +707,8 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data, > dma = vfio_find_dma(iommu, iova, PAGE_SIZE); > if (!dma) > goto unpin_exit; > - vfio_unpin_page_external(dma, iova, do_accounting); > + vfio_unpin_page_external(dma, iova, do_accounting, > + iommu->dirty_page_tracking, PAGE_SIZE); > } > > unpin_exit: > @@ -800,6 +896,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) > vfio_unmap_unpin(iommu, dma, true); > vfio_unlink_dma(iommu, dma); > put_task_struct(dma->task); > + kfree(dma->bitmap); > kfree(dma); > iommu->dma_avail++; > } > @@ -830,6 +927,54 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) > return bitmap; > } > > +static int vfio_iova_dirty_bitmap(struct vfio_iommu *iommu, dma_addr_t iova, > + size_t size, uint64_t pgsize, > + unsigned char __user *bitmap) > +{ > + struct vfio_dma *dma; > + unsigned long pgshift = __ffs(pgsize); > + unsigned int npages, bitmap_size; > + > + dma = vfio_find_dma(iommu, iova, 1); > + > + if (!dma) > + return -EINVAL; > + > + if (dma->iova != iova || dma->size != size) > + return -EINVAL; > + > + npages = dma->size >> pgshift; > + bitmap_size = dirty_bitmap_bytes(npages); > + > + /* mark all pages dirty if all pages are pinned and mapped. */ > + if (dma->iommu_mapped) > + bitmap_set(dma->bitmap, 0, npages); > + > + if (dma->bitmap) { > + if (copy_to_user((void __user *)bitmap, dma->bitmap, > + bitmap_size)) > + return -EFAULT; > + > + memset(dma->bitmap, 0, bitmap_size); > + } > + return 0; > +} > + > +static int verify_bitmap_size(unsigned long npages, unsigned long bitmap_size) > +{ > + long bsize; > + > + if (!bitmap_size || bitmap_size > SIZE_MAX) > + return -EINVAL; > + > + bsize = dirty_bitmap_bytes(npages); > + > + if (bitmap_size < bsize) > + return -EINVAL; > + > + return 0; > +} > + > static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > struct vfio_iommu_type1_dma_unmap *unmap) > { > @@ -2277,6 +2422,92 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > > return copy_to_user((void __user *)arg, &unmap, minsz) ? > -EFAULT : 0; > + } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) { > + struct vfio_iommu_type1_dirty_bitmap dirty; > + uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START | > + VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP | > + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP; > + int ret; > + > + if (!iommu->v2) > + return -EACCES; > + > + minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, > + flags); > + > + if (copy_from_user(&dirty, (void __user *)arg, minsz)) > + return -EFAULT; > + > + if (dirty.argsz < minsz || dirty.flags & ~mask) > + return -EINVAL; > + > + /* only one flag should be set at a time */ > + if (__ffs(dirty.flags) != __fls(dirty.flags)) > + return -EINVAL; It seems a bit odd to use a set of ORable flags when only one can be set at a time. > + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) { > + unsigned long iommu_pgsize = > + 1 << __ffs(vfio_pgsize_bitmap(iommu)); > + > + mutex_lock(&iommu->lock); > + ret = vfio_dma_all_bitmap_alloc(iommu, iommu_pgsize); > + if (!ret) > + iommu->dirty_page_tracking = true; > + mutex_unlock(&iommu->lock); > + return ret; > + } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) { > + mutex_lock(&iommu->lock); > + if (iommu->dirty_page_tracking) { > + iommu->dirty_page_tracking = false; > + vfio_dma_all_bitmap_free(iommu); > + } > + mutex_unlock(&iommu->lock); > + return 0; > + } else if (dirty.flags & > + VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) { > + struct vfio_iommu_type1_dirty_bitmap_get range; > + unsigned long pgshift; > + size_t data_size = dirty.argsz - minsz; > + uint64_t iommu_pgsize = > + 1 << __ffs(vfio_pgsize_bitmap(iommu)); > + > + if (!data_size || data_size < sizeof(range)) > + return -EINVAL; > + > + if (copy_from_user(&range, (void __user *)(arg + minsz), > + sizeof(range))) > + return -EFAULT; > + > + // allow only min supported pgsize > + if (range.pgsize != iommu_pgsize) > + return -EINVAL; > + if (range.iova & (iommu_pgsize - 1)) > + return -EINVAL; > + if (!range.size || range.size & (iommu_pgsize - 1)) > + return -EINVAL; > + if (range.iova + range.size < range.iova) > + return -EINVAL; > + if (!access_ok((void __user *)range.bitmap, > + range.bitmap_size)) > + return -EINVAL; > + > + pgshift = __ffs(range.pgsize); > + ret = verify_bitmap_size(range.size >> pgshift, > + range.bitmap_size); > + if (ret) > + return ret; > + > + mutex_lock(&iommu->lock); > + if (iommu->dirty_page_tracking) > + ret = vfio_iova_dirty_bitmap(iommu, range.iova, > + range.size, range.pgsize, > + (unsigned char __user *)range.bitmap); > + else > + ret = -EINVAL; > + mutex_unlock(&iommu->lock); > + > + return ret; > + } > } > > return -ENOTTY; > -- > 2.7.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK