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From: Yongji Xie <xieyongji@bytedance.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Stefan Hajnoczi" <stefanha@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Stefano Garzarella" <sgarzare@redhat.com>,
	"Parav Pandit" <parav@nvidia.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Christian Brauner" <christian.brauner@canonical.com>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Matthew Wilcox" <willy@infradead.org>,
	viro@zeniv.linux.org.uk, "Jens Axboe" <axboe@kernel.dk>,
	bcrl@kvack.org, "Jonathan Corbet" <corbet@lwn.net>,
	"Mika Penttilä" <mika.penttila@nextfour.com>,
	"Dan Carpenter" <dan.carpenter@oracle.com>,
	virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, kvm@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: Re: [PATCH v6 10/10] Documentation: Add documentation for VDUSE
Date: Thu, 15 Apr 2021 19:17:08 +0800	[thread overview]
Message-ID: <CACycT3tL7URz3n-KhMAwYH+Sn1e1TSyfU+RKcc8jpPDJ7WcZ2w@mail.gmail.com> (raw)
In-Reply-To: <02c19c22-13ea-ea97-d99b-71edfee0b703@redhat.com>

On Thu, Apr 15, 2021 at 5:05 PM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 在 2021/4/15 下午4:36, Jason Wang 写道:
> >>>
> >> Please state this explicitly at the start of the document. Existing
> >> interfaces like FUSE are designed to avoid trusting userspace.
> >
> >
> > There're some subtle difference here. VDUSE present a device to kernel
> > which means IOMMU is probably the only thing to prevent a malicous
> > device.
> >
> >
> >> Therefore
> >> people might think the same is the case here. It's critical that people
> >> are aware of this before deploying VDUSE with virtio-vdpa.
> >>
> >> We should probably pause here and think about whether it's possible to
> >> avoid trusting userspace. Even if it takes some effort and costs some
> >> performance it would probably be worthwhile.
> >
> >
> > Since the bounce buffer is used the only attack surface is the
> > coherent area, if we want to enforce stronger isolation we need to use
> > shadow virtqueue (which is proposed in earlier version by me) in this
> > case. But I'm not sure it's worth to do that.
>
>
>
> So this reminds me the discussion in the end of last year. We need to
> make sure we don't suffer from the same issues for VDUSE at least
>
> https://yhbt.net/lore/all/c3629a27-3590-1d9f-211b-c0b7be152b32@redhat.com/T/#mc6b6e2343cbeffca68ca7a97e0f473aaa871c95b
>
> Or we can solve it at virtio level, e.g remember the dma address instead
> of depending on the addr in the descriptor ring
>

I might miss something. But VDUSE has recorded the dma address during
dma mapping, so we would not do bouncing if the addr/length is invalid
during dma unmapping. Is it enough?

Thanks,
Yongji

  reply	other threads:[~2021-04-15 11:17 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
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 [this message]
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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