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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C2DE7C433DF for ; Fri, 15 May 2020 15:15:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 994A620728 for ; Fri, 15 May 2020 15:15:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ww20mL8n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbgEOPP5 (ORCPT ); Fri, 15 May 2020 11:15:57 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:40619 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726295AbgEOPP5 (ORCPT ); Fri, 15 May 2020 11:15:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589555754; 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=p0/M0lhsGgck9q4bh5uc5CG4I5IojC672QlJB9lODL4=; b=Ww20mL8nJmK3XL8du72OjYf0ehAOALoZ0c0iZF0x9XH6Y52k4O2vUE38ZQt7uHAqJ6JIGd iy2Y1wfdLXXZxbUcIXYzZ1fGL0YMhqBEVT6vFFhZxyy4XklvM8OVzT64eNp8BVzZC5m78H 9FYqvZ02Cmhb/NJTZyKdFVaqEtZ7WDg= 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-338-EbIgBuGTPNG1-P1sM3xPYQ-1; Fri, 15 May 2020 11:15:50 -0400 X-MC-Unique: EbIgBuGTPNG1-P1sM3xPYQ-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 6F2E98018AD; Fri, 15 May 2020 15:15:47 +0000 (UTC) Received: from w520.home (ovpn-112-50.phx2.redhat.com [10.3.112.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 124FB5D9F3; Fri, 15 May 2020 15:15:34 +0000 (UTC) Date: Fri, 15 May 2020 09:15:33 -0600 From: Alex Williamson To: Kirti Wankhede Cc: Yan Zhao , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH Kernel v20 5/8] vfio iommu: Implementation of ioctl for dirty pages tracking Message-ID: <20200515091533.53259392@w520.home> In-Reply-To: References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-6-git-send-email-kwankhede@nvidia.com> <20200515100553.GA5559@joy-OptiPlex-7040> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 15 May 2020 16:44:38 +0530 Kirti Wankhede wrote: > On 5/15/2020 3:35 PM, Yan Zhao wrote: > > On Fri, May 15, 2020 at 02:07:44AM +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 > >> > >> Fixed error reported by build bot by changing pgsize type from uint64_t > >> to size_t. > >> Reported-by: kbuild test robot > >> --- > >> drivers/vfio/vfio_iommu_type1.c | 294 +++++++++++++++++++++++++++++++++++++++- > >> 1 file changed, 288 insertions(+), 6 deletions(-) > >> > >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > >> index de17787ffece..b76d3b14abfd 100644 > >> --- a/drivers/vfio/vfio_iommu_type1.c > >> +++ b/drivers/vfio/vfio_iommu_type1.c > >> @@ -72,6 +72,7 @@ struct vfio_iommu { > >> uint64_t pgsize_bitmap; > >> bool v2; > >> bool nesting; > >> + bool dirty_page_tracking; > >> }; > >> > >> struct vfio_domain { > >> @@ -92,6 +93,7 @@ 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 { > >> @@ -126,6 +128,19 @@ 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) > >> + > >> +/* > >> + * Input argument of number of bits to bitmap_set() is unsigned integer, which > >> + * further casts to signed integer for unaligned multi-bit operation, > >> + * __bitmap_set(). > >> + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, > >> + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page > >> + * system. > >> + */ > >> +#define DIRTY_BITMAP_PAGES_MAX ((u64)INT_MAX) > >> +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) > >> + > >> static int put_pfn(unsigned long pfn, int prot); > >> > >> /* > >> @@ -176,6 +191,74 @@ 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_dma *dma, size_t pgsize) > >> +{ > >> + uint64_t npages = dma->size / pgsize; > >> + > >> + if (npages > DIRTY_BITMAP_PAGES_MAX) > >> + return -EINVAL; > >> + > >> + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); > >> + if (!dma->bitmap) > >> + return -ENOMEM; > >> + > >> + return 0; > >> +} > >> + > >> +static void vfio_dma_bitmap_free(struct vfio_dma *dma) > >> +{ > >> + kfree(dma->bitmap); > >> + dma->bitmap = NULL; > >> +} > >> + > >> +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize) > >> +{ > >> + struct rb_node *p; > >> + > >> + 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); > >> + } > >> +} > >> + > >> +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_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); > >> + int ret; > >> + > >> + 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); > >> + > >> + vfio_dma_bitmap_free(dma); > >> + } > >> + return ret; > >> + } > >> + vfio_dma_populate_bitmap(dma, pgsize); > >> + } > >> + return 0; > >> +} > >> + > >> +static void vfio_dma_bitmap_free_all(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); > >> + > >> + vfio_dma_bitmap_free(dma); > >> + } > >> +} > >> + > >> /* > >> * Helper Functions for host iova-pfn list > >> */ > >> @@ -568,6 +651,17 @@ 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(iommu->pgsize_bitmap); > >> + > >> + /* > >> + * Bitmap populated with the smallest supported page > >> + * size > >> + */ > >> + bitmap_set(dma->bitmap, > >> + (vpfn->iova - dma->iova) >> pgshift, 1); > >> + } > >> } > >> > >> ret = i; > >> @@ -802,6 +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); > >> + vfio_dma_bitmap_free(dma); > >> kfree(dma); > >> iommu->dma_avail++; > >> } > >> @@ -829,6 +924,80 @@ static void vfio_pgsize_bitmap(struct vfio_iommu *iommu) > >> } > >> } > >> > >> +static int update_user_bitmap(u64 __user *bitmap, struct vfio_dma *dma, > >> + dma_addr_t base_iova, size_t pgsize) > >> +{ > >> + unsigned long pgshift = __ffs(pgsize); > >> + unsigned long nbits = dma->size >> pgshift; > >> + unsigned long bit_offset = (dma->iova - base_iova) >> pgshift; > >> + unsigned long copy_offset = bit_offset / BITS_PER_LONG; > >> + unsigned long shift = bit_offset % BITS_PER_LONG; > >> + unsigned long leftover; > >> + > >> + if (shift) { > >> + bitmap_shift_left(dma->bitmap, dma->bitmap, shift, > >> + nbits + shift); > >> + > >> + if (copy_from_user(&leftover, (u64 *)bitmap + copy_offset, > >> + sizeof(leftover))) > >> + return -EFAULT; > >> + > >> + bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift); > >> + } > >> + > >> + if (copy_to_user((u64 *)bitmap + copy_offset, dma->bitmap, > >> + DIRTY_BITMAP_BYTES(nbits + shift))) > >> + return -EFAULT; > >> + > >> + return 0; > >> +} > >> + > >> +static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu, > >> + dma_addr_t iova, size_t size, size_t pgsize) > >> +{ > >> + struct vfio_dma *dma; > >> + dma_addr_t i = iova, limit = iova + size; > >> + unsigned long pgshift = __ffs(pgsize); > >> + size_t sz = size; > >> + int ret; > >> + > >> + while ((dma = vfio_find_dma(iommu, i, sz))) { > > not quite get the logic here. > > if (i, i + size) is intersecting with (dma->iova, dma->iova + dma->size), > > and a dma is found here, why the whole bitmap is cleared and copied? > > > > This works with multiple but full vfio_dma, not intersects of vfio_dma, > similar to unmap ioctl. I don't see that the VFIO_IOMMU_DIRTY_PAGES ioctl validates that like VFIO_IOMMU_UNMAP_DMA does though. We should have the same test as vfio_dma_do_unmap() to verify that they user range doesn't bisect a mapping, otherwise Yan is right, it looks like we allow the user to specify an arbitrary range that might bisect a bitmap, but we clear and attempt to copy the entire bitmap to the user buffer regardless. Thanks, Alex 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=-6.6 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 EE029C433DF for ; Fri, 15 May 2020 15:23:01 +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 BC21520671 for ; Fri, 15 May 2020 15:23:00 +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="Ww20mL8n" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC21520671 Authentication-Results: mail.kernel.org; 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Fri, 15 May 2020 15:15:34 +0000 (UTC) Date: Fri, 15 May 2020 09:15:33 -0600 From: Alex Williamson To: Kirti Wankhede Subject: Re: [PATCH Kernel v20 5/8] vfio iommu: Implementation of ioctl for dirty pages tracking Message-ID: <20200515091533.53259392@w520.home> In-Reply-To: References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-6-git-send-email-kwankhede@nvidia.com> <20200515100553.GA5559@joy-OptiPlex-7040> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Received-SPF: pass client-ip=205.139.110.61; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/15 00:07:24 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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 Zhao , changpeng.liu@intel.com, Ken.Xue@amd.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 15 May 2020 16:44:38 +0530 Kirti Wankhede wrote: > On 5/15/2020 3:35 PM, Yan Zhao wrote: > > On Fri, May 15, 2020 at 02:07:44AM +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 > >> > >> Fixed error reported by build bot by changing pgsize type from uint64_t > >> to size_t. > >> Reported-by: kbuild test robot > >> --- > >> drivers/vfio/vfio_iommu_type1.c | 294 +++++++++++++++++++++++++++++++++++++++- > >> 1 file changed, 288 insertions(+), 6 deletions(-) > >> > >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > >> index de17787ffece..b76d3b14abfd 100644 > >> --- a/drivers/vfio/vfio_iommu_type1.c > >> +++ b/drivers/vfio/vfio_iommu_type1.c > >> @@ -72,6 +72,7 @@ struct vfio_iommu { > >> uint64_t pgsize_bitmap; > >> bool v2; > >> bool nesting; > >> + bool dirty_page_tracking; > >> }; > >> > >> struct vfio_domain { > >> @@ -92,6 +93,7 @@ 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 { > >> @@ -126,6 +128,19 @@ 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) > >> + > >> +/* > >> + * Input argument of number of bits to bitmap_set() is unsigned integer, which > >> + * further casts to signed integer for unaligned multi-bit operation, > >> + * __bitmap_set(). > >> + * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte, > >> + * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page > >> + * system. > >> + */ > >> +#define DIRTY_BITMAP_PAGES_MAX ((u64)INT_MAX) > >> +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) > >> + > >> static int put_pfn(unsigned long pfn, int prot); > >> > >> /* > >> @@ -176,6 +191,74 @@ 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_dma *dma, size_t pgsize) > >> +{ > >> + uint64_t npages = dma->size / pgsize; > >> + > >> + if (npages > DIRTY_BITMAP_PAGES_MAX) > >> + return -EINVAL; > >> + > >> + dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages), GFP_KERNEL); > >> + if (!dma->bitmap) > >> + return -ENOMEM; > >> + > >> + return 0; > >> +} > >> + > >> +static void vfio_dma_bitmap_free(struct vfio_dma *dma) > >> +{ > >> + kfree(dma->bitmap); > >> + dma->bitmap = NULL; > >> +} > >> + > >> +static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize) > >> +{ > >> + struct rb_node *p; > >> + > >> + 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); > >> + } > >> +} > >> + > >> +static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_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); > >> + int ret; > >> + > >> + 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); > >> + > >> + vfio_dma_bitmap_free(dma); > >> + } > >> + return ret; > >> + } > >> + vfio_dma_populate_bitmap(dma, pgsize); > >> + } > >> + return 0; > >> +} > >> + > >> +static void vfio_dma_bitmap_free_all(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); > >> + > >> + vfio_dma_bitmap_free(dma); > >> + } > >> +} > >> + > >> /* > >> * Helper Functions for host iova-pfn list > >> */ > >> @@ -568,6 +651,17 @@ 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(iommu->pgsize_bitmap); > >> + > >> + /* > >> + * Bitmap populated with the smallest supported page > >> + * size > >> + */ > >> + bitmap_set(dma->bitmap, > >> + (vpfn->iova - dma->iova) >> pgshift, 1); > >> + } > >> } > >> > >> ret = i; > >> @@ -802,6 +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); > >> + vfio_dma_bitmap_free(dma); > >> kfree(dma); > >> iommu->dma_avail++; > >> } > >> @@ -829,6 +924,80 @@ static void vfio_pgsize_bitmap(struct vfio_iommu *iommu) > >> } > >> } > >> > >> +static int update_user_bitmap(u64 __user *bitmap, struct vfio_dma *dma, > >> + dma_addr_t base_iova, size_t pgsize) > >> +{ > >> + unsigned long pgshift = __ffs(pgsize); > >> + unsigned long nbits = dma->size >> pgshift; > >> + unsigned long bit_offset = (dma->iova - base_iova) >> pgshift; > >> + unsigned long copy_offset = bit_offset / BITS_PER_LONG; > >> + unsigned long shift = bit_offset % BITS_PER_LONG; > >> + unsigned long leftover; > >> + > >> + if (shift) { > >> + bitmap_shift_left(dma->bitmap, dma->bitmap, shift, > >> + nbits + shift); > >> + > >> + if (copy_from_user(&leftover, (u64 *)bitmap + copy_offset, > >> + sizeof(leftover))) > >> + return -EFAULT; > >> + > >> + bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift); > >> + } > >> + > >> + if (copy_to_user((u64 *)bitmap + copy_offset, dma->bitmap, > >> + DIRTY_BITMAP_BYTES(nbits + shift))) > >> + return -EFAULT; > >> + > >> + return 0; > >> +} > >> + > >> +static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu, > >> + dma_addr_t iova, size_t size, size_t pgsize) > >> +{ > >> + struct vfio_dma *dma; > >> + dma_addr_t i = iova, limit = iova + size; > >> + unsigned long pgshift = __ffs(pgsize); > >> + size_t sz = size; > >> + int ret; > >> + > >> + while ((dma = vfio_find_dma(iommu, i, sz))) { > > not quite get the logic here. > > if (i, i + size) is intersecting with (dma->iova, dma->iova + dma->size), > > and a dma is found here, why the whole bitmap is cleared and copied? > > > > This works with multiple but full vfio_dma, not intersects of vfio_dma, > similar to unmap ioctl. I don't see that the VFIO_IOMMU_DIRTY_PAGES ioctl validates that like VFIO_IOMMU_UNMAP_DMA does though. We should have the same test as vfio_dma_do_unmap() to verify that they user range doesn't bisect a mapping, otherwise Yan is right, it looks like we allow the user to specify an arbitrary range that might bisect a bitmap, but we clear and attempt to copy the entire bitmap to the user buffer regardless. Thanks, Alex