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 A1AE4C4332B for ; Thu, 19 Mar 2020 03:47:58 +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 5A1A920722 for ; Thu, 19 Mar 2020 03:47:58 +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="IZ4RMwQ2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A1A920722 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]:33006 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEmA1-0003gg-Hf for qemu-devel@archiver.kernel.org; Wed, 18 Mar 2020 23:47:57 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55778) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEm7M-0000kM-Sj for qemu-devel@nongnu.org; Wed, 18 Mar 2020 23:45:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEm7K-0007A0-Vu for qemu-devel@nongnu.org; Wed, 18 Mar 2020 23:45:12 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:58831) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEm7K-00076R-Mu for qemu-devel@nongnu.org; Wed, 18 Mar 2020 23:45:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584589509; 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=P5JpO8HSA4DOLAbbeuAZRqMoH3/gVv4FN1Ksuqh3kYM=; b=IZ4RMwQ2SNyZ17wYQ+cR/5+O7voTer12HJE3mpaQIWIppVjDNA6z0xuE/atof1YNSNoFnf 1Vy4HWJH3lVHKEb32dbspZnxwBwmJGBRfY26Snd41WIxrslOkAg1xt0+oC13gfNjs9djwK 6ktCJqioIdkGVsTg+Hb3KtRGJ16LYLc= 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-400-utBeOXQqM4-byx_ZVHmL4Q-1; Wed, 18 Mar 2020 23:45:05 -0400 X-MC-Unique: utBeOXQqM4-byx_ZVHmL4Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AC4E48017CE; Thu, 19 Mar 2020 03:45:02 +0000 (UTC) Received: from w520.home (ovpn-112-162.phx2.redhat.com [10.3.112.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id 32058BBBC5; Thu, 19 Mar 2020 03:45:01 +0000 (UTC) Date: Wed, 18 Mar 2020 21:45:00 -0600 From: Alex Williamson To: Kirti Wankhede Subject: Re: [PATCH v14 Kernel 4/7] vfio iommu: Implementation of ioctl for dirty pages tracking. Message-ID: <20200318214500.1a0cb985@w520.home> In-Reply-To: <1584560474-19946-5-git-send-email-kwankhede@nvidia.com> References: <1584560474-19946-1-git-send-email-kwankhede@nvidia.com> <1584560474-19946-5-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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, qemu-devel@nongnu.org, cohuck@redhat.com, shuangtai.tst@alibaba-inc.com, dgilbert@redhat.com, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, 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 Thu, 19 Mar 2020 01:11:11 +0530 Kirti Wankhede wrote: > VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations: > - Start dirty pages tracking while migration is active > - Stop dirty pages tracking. > - Get dirty pages bitmap. Its user space application's 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 for all vfio_dmas when dirty logging is enabled > > 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 functions when tracking is enabled. 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 | 205 +++++++++++++++++++++++++++++++++++++++- > 1 file changed, 203 insertions(+), 2 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 70aeab921d0f..d6417fb02174 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -71,6 +71,7 @@ struct vfio_iommu { > unsigned int dma_avail; > bool v2; > bool nesting; > + bool dirty_page_tracking; > }; > > struct vfio_domain { > @@ -91,6 +92,7 @@ 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; We've made the bitmap a width invariant u64 else, should be here as well. > }; > > struct vfio_group { > @@ -125,7 +127,10 @@ struct vfio_regions { > #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ > (!list_empty(&iommu->domain_list)) > > +#define DIRTY_BITMAP_BYTES(n) (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE) > + > 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 > @@ -175,6 +180,55 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) > rb_erase(&old->node, &iommu->dma_list); > } > > +static int vfio_dma_bitmap_alloc(struct vfio_iommu *iommu, uint64_t pgsize) > +{ > + 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); > + struct rb_node *p; > + unsigned long npages = dma->size / pgsize; > + > + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); > + if (!dma->bitmap) { > + 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 -ENOMEM; > + } > + > + if (RB_EMPTY_ROOT(&dma->pfn_list)) > + continue; > + > + for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) { > + struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, > + node); > + > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) / pgsize, 1); > + } > + } > + return 0; > +} > + > +static void vfio_dma_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 > */ > @@ -567,6 +621,14 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > vfio_unpin_page_external(dma, iova, do_accounting); > goto pin_unwind; > } > + > + if (iommu->dirty_page_tracking) { > + unsigned long pgshift = > + __ffs(vfio_pgsize_bitmap(iommu)); > + > + bitmap_set(dma->bitmap, > + (vpfn->iova - dma->iova) >> pgshift, 1); > + } > } > > ret = i; > @@ -801,6 +863,7 @@ 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++; > } > @@ -831,6 +894,50 @@ 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) And here, why do callers cast to an unsigned char pointer when we're going to cast to a void pointer anyway? Should be a u64 __user pointer. > +{ > + 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 (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) > + return -EFAULT; > + > + return 0; > +} > + > +static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) > +{ > + uint64_t bsize; > + > + if (!npages || !bitmap_size || bitmap_size > UINT_MAX) As commented previously, how do we derive this UINT_MAX limitation? > + 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) > { We didn't address that vfio_dma_do_map() needs to kvzalloc a bitmap for any new vfio_dma created while iommu->dirty_page_tracking = true. > @@ -2278,6 +2385,93 @@ 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 = 0; > + > + 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; > + > + if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) { > + uint64_t pgsize = 1 << __ffs(vfio_pgsize_bitmap(iommu)); > + > + mutex_lock(&iommu->lock); > + if (!iommu->dirty_page_tracking) { > + ret = vfio_dma_bitmap_alloc(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_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.bitmap.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.data, > + range.bitmap.size)) > + return -EINVAL; > + > + pgshift = __ffs(range.bitmap.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.bitmap.pgsize, > + (unsigned char __user *)range.bitmap.data); > + else > + ret = -EINVAL; > + mutex_unlock(&iommu->lock); > + > + return ret; > + } > } > > return -ENOTTY; > @@ -2345,10 +2539,17 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu, > > vaddr = dma->vaddr + offset; > > - if (write) > + if (write) { > *copied = __copy_to_user((void __user *)vaddr, data, > count) ? 0 : count; > - else > + if (*copied && iommu->dirty_page_tracking) { > + unsigned long pgshift = > + __ffs(vfio_pgsize_bitmap(iommu)); > + > + bitmap_set(dma->bitmap, offset >> pgshift, > + *copied >> pgshift); > + } > + } else Great, thanks for adding this! > *copied = __copy_from_user(data, (void __user *)vaddr, > count) ? 0 : count; > if (kthread)