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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 1D121C43331 for ; Tue, 31 Mar 2020 00:20:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD3E620771 for ; Tue, 31 Mar 2020 00:20:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729398AbgCaAUH (ORCPT ); Mon, 30 Mar 2020 20:20:07 -0400 Received: from mga18.intel.com ([134.134.136.126]:14522 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729019AbgCaAUH (ORCPT ); Mon, 30 Mar 2020 20:20:07 -0400 IronPort-SDR: u/nEV1gHfOMk7PR0s4dkodeqZH7DCUBRjc2/uBzd8MvYMy4SsI977s6q1R0q+bhADkQ4QzJKnG 7Nom08nkSWgg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2020 17:20:06 -0700 IronPort-SDR: VEGZMBuPruyzsdAz9DY2v9+OKGPBGiGChK2ilh37+/PsMdE43ekbKlkjXqJi+M56Nf1mM49+8x h883/84sOGrw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,326,1580803200"; d="scan'208";a="272556725" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by fmsmga004.fm.intel.com with ESMTP; 30 Mar 2020 17:20:01 -0700 Date: Mon, 30 Mar 2020 20:10:28 -0400 From: Yan Zhao To: Alex Williamson Cc: Kirti Wankhede , "cjia@nvidia.com" , "Tian, Kevin" , "Yang, Ziye" , "Liu, Changpeng" , "Liu, Yi L" , "mlevitsk@redhat.com" , "eskultet@redhat.com" , "cohuck@redhat.com" , "dgilbert@redhat.com" , "jonathan.davies@nutanix.com" , "eauger@redhat.com" , "aik@ozlabs.ru" , "pasic@linux.ibm.com" , "felipe@nutanix.com" , "Zhengxiao.zx@Alibaba-inc.com" , "shuangtai.tst@alibaba-inc.com" , "Ken.Xue@amd.com" , "Wang, Zhi A" , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" Subject: Re: [PATCH v17 Kernel 4/7] vfio iommu: Implementation of ioctl for dirty pages tracking. Message-ID: <20200331001027.GA6631@joy-OptiPlex-7040> Reply-To: Yan Zhao References: <1585587044-2408-1-git-send-email-kwankhede@nvidia.com> <1585587044-2408-5-git-send-email-kwankhede@nvidia.com> <20200330151909.71da1f91@w520.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200330151909.71da1f91@w520.home> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Mar 31, 2020 at 05:19:09AM +0800, Alex Williamson wrote: > On Mon, 30 Mar 2020 22:20:41 +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. > > > > Fixed below error by changing pgsize type from uint64_t to size_t. > > Reported-by: kbuild test robot > > > > All errors: > > drivers/vfio/vfio_iommu_type1.c:197: undefined reference to `__udivdi3' > > > > drivers/vfio/vfio_iommu_type1.c:225: undefined reference to `__udivdi3' > > > > Signed-off-by: Kirti Wankhede > > Reviewed-by: Neo Jia > > --- > > drivers/vfio/vfio_iommu_type1.c | 266 +++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 260 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > > index 70aeab921d0f..5efebc2b60e1 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; > > }; > > > > struct vfio_group { > > @@ -125,7 +127,21 @@ 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 (uint64_t)(INT_MAX - 1) > > > This was supposed to be (INT_MAX), not (INT_MAX - 1). Thanks, > > Alex > > > > +#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX) > > + > > 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 +191,77 @@ 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; > > + > > + if (RB_EMPTY_ROOT(&dma->pfn_list)) > > + return; > > + > > + 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 > > */ > > @@ -567,6 +654,18 @@ 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 populated with the smallest supported page > > + * size > > + */ > > + bitmap_set(dma->bitmap, > > + (vpfn->iova - dma->iova) >> pgshift, 1); > > + } > > } > > > > ret = i; > > @@ -801,6 +900,7 @@ 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++; > > } > > @@ -831,6 +931,57 @@ 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, size_t pgsize, > > + u64 __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 (copy_to_user((void __user *)bitmap, dma->bitmap, bitmap_size)) > > + return -EFAULT; > > + > > + /* > > + * Re-populate bitmap to include all pinned pages which are considered > > + * as dirty but exclude pages which are unpinned and pages which are > > + * marked dirty by vfio_dma_rw() > > + */ > > + bitmap_clear(dma->bitmap, 0, npages); > > + vfio_dma_populate_bitmap(dma, pgsize); > > + return 0; > > +} > > + > > +static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size) > > +{ > > + uint64_t bsize; > > + > > + if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_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) > > { > > @@ -1038,16 +1189,16 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > > unsigned long vaddr = map->vaddr; > > size_t size = map->size; > > int ret = 0, prot = 0; > > - uint64_t mask; > > + size_t pgsize; > > struct vfio_dma *dma; > > > > /* Verify that none of our __u64 fields overflow */ > > if (map->size != size || map->vaddr != vaddr || map->iova != iova) > > return -EINVAL; > > > > - mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; > > + pgsize = (size_t)1 << __ffs(vfio_pgsize_bitmap(iommu)); > > > > - WARN_ON(mask & PAGE_MASK); > > + WARN_ON((pgsize - 1) & PAGE_MASK); > > > > /* READ/WRITE from device perspective */ > > if (map->flags & VFIO_DMA_MAP_FLAG_WRITE) > > @@ -1055,7 +1206,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > > if (map->flags & VFIO_DMA_MAP_FLAG_READ) > > prot |= IOMMU_READ; > > > > - if (!prot || !size || (size | iova | vaddr) & mask) > > + if (!prot || !size || (size | iova | vaddr) & (pgsize - 1)) > > return -EINVAL; > > > > /* Don't allow IOVA or virtual address wrap */ > > @@ -1130,6 +1281,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > > else > > ret = vfio_pin_map_dma(iommu, dma, size); > > > > + if (!ret && iommu->dirty_page_tracking) { > > + ret = vfio_dma_bitmap_alloc(dma, pgsize); > > + if (ret) > > + vfio_remove_dma(iommu, dma); > > + } > > + > > out_unlock: > > mutex_unlock(&iommu->lock); > > return ret; > > @@ -2278,6 +2435,93 @@ 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) { > > + size_t pgsize = 1 << __ffs(vfio_pgsize_bitmap(iommu)); > > + should not use smallest iommu page size as pgsize here as well as for bitmap_set. qemu uses 4k for dirty page track. > > + mutex_lock(&iommu->lock); > > + if (!iommu->dirty_page_tracking) { > > + ret = vfio_dma_bitmap_alloc_all(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_all(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; > > + size_t iommu_pgsize = > > + (size_t)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 smallest 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, > > + range.bitmap.data); > > + else > > + ret = -EINVAL; > > + mutex_unlock(&iommu->lock); > > + > > + return ret; > > + } > > } > > > > return -ENOTTY; > > @@ -2345,10 +2589,20 @@ 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 populated with the smallest supported page > > + * size > > + */ > > + bitmap_set(dma->bitmap, offset >> pgshift, > > + *copied >> pgshift); > > + } > > + } else > > *copied = __copy_from_user(data, (void __user *)vaddr, > > count) ? 0 : count; > > if (kthread) >