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=-6.5 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 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 BC184C10DCE for ; Wed, 18 Mar 2020 13:34:21 +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 65A2E20772 for ; Wed, 18 Mar 2020 13:34:21 +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="ChA/4ASr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65A2E20772 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]:50834 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEYpw-0001vD-Dh for qemu-devel@archiver.kernel.org; Wed, 18 Mar 2020 09:34:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60064) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEYoA-0000Nv-Kn for qemu-devel@nongnu.org; Wed, 18 Mar 2020 09:32:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEYo8-0003yI-4f for qemu-devel@nongnu.org; Wed, 18 Mar 2020 09:32:30 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:29534) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEYo7-0003uQ-UV for qemu-devel@nongnu.org; Wed, 18 Mar 2020 09:32:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584538347; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c9g8r2ENRbNRt1kTIM38bxnse1ZhPdTPzvX0av73c0g=; b=ChA/4ASrCzZvvlrZCWMVjXmQr+srj+PMv9PozDDya6IYMrdh4yEPQUwijyGOcApnkKfDrP BTvSBoLLvhyVXiFO4OM4crgBUHUohO5XKsTSxu4vInqXWeYVL0qbAwL+yuRi94gJf9MTaf KXq2JhVuLet4TMAraRt6I5ADBzN3Zso= 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-376-ZxkK7nFlNIqKIWFVZ-tvBw-1; Wed, 18 Mar 2020 09:32:21 -0400 X-MC-Unique: ZxkK7nFlNIqKIWFVZ-tvBw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B6F1B190B2C9; Wed, 18 Mar 2020 13:32:17 +0000 (UTC) Received: from x1.home (ovpn-112-162.phx2.redhat.com [10.3.112.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id D692819C6A; Wed, 18 Mar 2020 13:32:15 +0000 (UTC) Date: Wed, 18 Mar 2020 07:32:15 -0600 From: Alex Williamson To: "Dr. David Alan Gilbert" Subject: Re: [PATCH v13 Kernel 4/7] vfio iommu: Implementation of ioctl to for dirty pages tracking. Message-ID: <20200318073215.1e77d0a2@x1.home> In-Reply-To: <20200318121312.GI2850@work-vm> References: <1584035607-23166-1-git-send-email-kwankhede@nvidia.com> <1584035607-23166-5-git-send-email-kwankhede@nvidia.com> <20200318121312.GI2850@work-vm> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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, Kirti Wankhede , 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" On Wed, 18 Mar 2020 12:13:12 +0000 "Dr. David Alan Gilbert" wrote: > * 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. Is it really? It might in the future be true that there are some combination of flags that are valid, but for the currently defined flags, they're mutually exclusive. There's no combination of START | STOP | GET that makes sense. Don't read into the current implementation that this is fixed in the API except as it relates to the currently defined flags. Thanks, Alex > > + 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