From: Jason Wang <jasowang@redhat.com>
To: Xie Yongji <xieyongji@bytedance.com>,
mst@redhat.com, stefanha@redhat.com, sgarzare@redhat.com,
parav@nvidia.com, hch@infradead.org,
christian.brauner@canonical.com, rdunlap@infradead.org,
willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk,
bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com,
dan.carpenter@oracle.com
Cc: virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, kvm@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v6 08/10] vduse: Implement an MMU-based IOMMU driver
Date: Thu, 8 Apr 2021 11:25:49 +0800 [thread overview]
Message-ID: <30862242-293b-f42f-d8ce-2c31a52e3697@redhat.com> (raw)
In-Reply-To: <20210331080519.172-9-xieyongji@bytedance.com>
在 2021/3/31 下午4:05, Xie Yongji 写道:
> This implements an MMU-based IOMMU driver to support mapping
> kernel dma buffer into userspace. The basic idea behind it is
> treating MMU (VA->PA) as IOMMU (IOVA->PA). The driver will set
> up MMU mapping instead of IOMMU mapping for the DMA transfer so
> that the userspace process is able to use its virtual address to
> access the dma buffer in kernel.
>
> And to avoid security issue, a bounce-buffering mechanism is
> introduced to prevent userspace accessing the original buffer
> directly.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
With some nits:
> ---
> drivers/vdpa/vdpa_user/iova_domain.c | 521 +++++++++++++++++++++++++++++++++++
> drivers/vdpa/vdpa_user/iova_domain.h | 70 +++++
> 2 files changed, 591 insertions(+)
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
[...]
> +static void vduse_domain_bounce(struct vduse_iova_domain *domain,
> + dma_addr_t iova, size_t size,
> + enum dma_data_direction dir)
> +{
> + struct vduse_bounce_map *map;
> + unsigned int offset;
> + void *addr;
> + size_t sz;
> +
> + while (size) {
> + map = &domain->bounce_maps[iova >> PAGE_SHIFT];
> + offset = offset_in_page(iova);
> + sz = min_t(size_t, PAGE_SIZE - offset, size);
> +
> + if (WARN_ON(!map->bounce_page ||
> + map->orig_phys == INVALID_PHYS_ADDR))
> + return;
> +
> + addr = page_address(map->bounce_page) + offset;
> + do_bounce(map->orig_phys + offset, addr, sz, dir);
> + size -= sz;
> + iova += sz;
> + }
> +}
> +
> +static struct page *
> +vduse_domain_get_mapping_page(struct vduse_iova_domain *domain, u64 iova)
It's better to rename this as "vduse_domain_get_coherent_page?".
> +{
> + u64 start = iova & PAGE_MASK;
> + u64 last = start + PAGE_SIZE - 1;
> + struct vhost_iotlb_map *map;
> + struct page *page = NULL;
> +
> + spin_lock(&domain->iotlb_lock);
> + map = vhost_iotlb_itree_first(domain->iotlb, start, last);
> + if (!map)
> + goto out;
> +
> + page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);
> + get_page(page);
> +out:
> + spin_unlock(&domain->iotlb_lock);
> +
> + return page;
> +}
> +
[...]
> +
> +static dma_addr_t
> +vduse_domain_alloc_iova(struct iova_domain *iovad,
> + unsigned long size, unsigned long limit)
> +{
> + unsigned long shift = iova_shift(iovad);
> + unsigned long iova_len = iova_align(iovad, size) >> shift;
> + unsigned long iova_pfn;
> +
> + if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
> + iova_len = roundup_pow_of_two(iova_len);
Let's add a comment as what has been done in dma-iommu.c?
(In the future, it looks to me it's better to move them to
alloc_iova_fast()).
Thanks
next prev parent reply other threads:[~2021-04-08 3:26 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 8:05 [PATCH v6 00/10] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-03-31 8:05 ` [PATCH v6 01/10] file: Export receive_fd() to modules Xie Yongji
2021-03-31 9:15 ` Christian Brauner
2021-03-31 9:26 ` Dan Carpenter
2021-03-31 9:28 ` Christian Brauner
2021-03-31 11:32 ` Yongji Xie
2021-03-31 12:23 ` Christian Brauner
2021-03-31 13:59 ` Yongji Xie
2021-03-31 14:07 ` Christian Brauner
2021-03-31 14:37 ` Yongji Xie
2021-03-31 8:05 ` [PATCH v6 02/10] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
2021-03-31 8:05 ` [PATCH v6 03/10] vhost-vdpa: protect concurrent access to vhost device iotlb Xie Yongji
2021-04-09 16:15 ` Michael S. Tsirkin
2021-04-11 5:36 ` Yongji Xie
2021-04-11 20:48 ` Michael S. Tsirkin
2021-04-12 2:29 ` Yongji Xie
2021-04-12 9:00 ` Michael S. Tsirkin
2021-03-31 8:05 ` [PATCH v6 04/10] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji
2021-03-31 8:05 ` [PATCH v6 05/10] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji
2021-03-31 8:05 ` [PATCH v6 06/10] vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap() Xie Yongji
2021-03-31 8:05 ` [PATCH v6 07/10] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji
2021-04-08 2:36 ` Jason Wang
2021-03-31 8:05 ` [PATCH v6 08/10] vduse: Implement an MMU-based IOMMU driver Xie Yongji
2021-04-08 3:25 ` Jason Wang [this message]
2021-04-08 5:27 ` Yongji Xie
2021-03-31 8:05 ` [PATCH v6 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2021-04-08 6:57 ` Jason Wang
2021-04-08 9:36 ` Yongji Xie
2021-04-09 5:36 ` Jason Wang
2021-04-09 8:02 ` Yongji Xie
2021-04-12 7:16 ` Jason Wang
2021-04-12 8:02 ` Yongji Xie
2021-04-12 9:37 ` Jason Wang
2021-04-12 9:59 ` Yongji Xie
2021-04-13 3:35 ` Jason Wang
2021-04-13 4:28 ` Yongji Xie
2021-04-14 8:18 ` Jason Wang
2021-04-16 3:24 ` Jason Wang
2021-04-16 8:43 ` Yongji Xie
2021-03-31 8:05 ` [PATCH v6 10/10] Documentation: Add documentation for VDUSE Xie Yongji
2021-04-08 7:18 ` Jason Wang
2021-04-08 8:09 ` Yongji Xie
2021-04-14 14:14 ` Stefan Hajnoczi
2021-04-15 5:38 ` Yongji Xie
2021-04-15 7:19 ` Stefan Hajnoczi
2021-04-15 8:33 ` Yongji Xie
2021-04-15 14:17 ` Stefan Hajnoczi
2021-04-15 8:36 ` Jason Wang
2021-04-15 9:04 ` Jason Wang
2021-04-15 11:17 ` Yongji Xie
2021-04-16 2:20 ` Jason Wang
2021-04-16 2:58 ` Yongji Xie
2021-04-16 3:02 ` Jason Wang
2021-04-16 3:18 ` Yongji Xie
2021-04-15 14:38 ` Stefan Hajnoczi
2021-04-16 2:23 ` Jason Wang
2021-04-16 3:19 ` Yongji Xie
2021-04-16 5:39 ` Jason Wang
2021-04-16 3:13 ` Yongji Xie
2021-04-14 7:34 ` [PATCH v6 00/10] Introduce VDUSE - vDPA Device in Userspace Michael S. Tsirkin
2021-04-14 7:49 ` Jason Wang
2021-04-14 7:54 ` Yongji Xie
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