From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Johannes Berg <johannes@sipsolutions.net>,
"Michael S. Tsirkin" <mst@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Hans de Goede <hdegoede@redhat.com>,
Mark Gross <markgross@kernel.org>,
Vadim Pasternak <vadimp@nvidia.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Cornelia Huck <cohuck@redhat.com>,
Halil Pasic <pasic@linux.ibm.com>,
Eric Farman <farman@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Vincent Whitchurch <vincent.whitchurch@axis.com>,
linux-um@lists.infradead.org, netdev@vger.kernel.org,
platform-driver-x86@vger.kernel.org,
linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org,
kvm@vger.kernel.org, bpf@vger.kernel.org,
kangjie.xu@linux.alibaba.com,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v11 21/40] virtio_ring: packed: introduce virtqueue_resize_packed()
Date: Mon, 4 Jul 2022 10:13:32 +0800 [thread overview]
Message-ID: <1656900812.860175-2-xuanzhuo@linux.alibaba.com> (raw)
In-Reply-To: <de7cf56d-acbd-1a2b-2226-a9fdd89afb78@redhat.com>
On Fri, 1 Jul 2022 17:27:48 +0800, Jason Wang <jasowang@redhat.com> wrote:
>
> 在 2022/6/29 14:56, Xuan Zhuo 写道:
> > virtio ring packed supports resize.
> >
> > Only after the new vring is successfully allocated based on the new num,
> > we will release the old vring. In any case, an error is returned,
> > indicating that the vring still points to the old vring.
> >
> > In the case of an error, re-initialize(by virtqueue_reinit_packed()) the
> > virtqueue to ensure that the vring can be used.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> > drivers/virtio/virtio_ring.c | 29 +++++++++++++++++++++++++++++
> > 1 file changed, 29 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 650f701a5480..4860787286db 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -2042,6 +2042,35 @@ static struct virtqueue *vring_create_virtqueue_packed(
> > return NULL;
> > }
> >
> > +static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
> > +{
> > + struct vring_virtqueue_packed vring = {};
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > + struct virtio_device *vdev = _vq->vdev;
> > + int err;
> > +
> > + if (vring_alloc_queue_packed(&vring, vdev, num))
> > + goto err_ring;
> > +
> > + err = vring_alloc_state_extra_packed(&vring);
> > + if (err)
> > + goto err_state_extra;
> > +
> > + vring_free(&vq->vq);
> > +
> > + virtqueue_init(vq, vring.vring.num);
> > + virtqueue_vring_attach_packed(vq, &vring);
> > + virtqueue_vring_init_packed(vq);
> > +
> > + return 0;
> > +
> > +err_state_extra:
> > + vring_free_packed(&vring, vdev);
> > +err_ring:
> > + virtqueue_reinit_packed(vq);
>
>
> So desc_state and desc_extra has been freed vring_free_packed() when
> vring_alloc_state_extra_packed() fails. We might get use-after-free here?
vring_free_packed() frees the temporary structure vring. It does not affect
desc_state and desc_extra of vq. So it is safe.
>
> Actually, I think for resize we need
>
> 1) detach old
> 2) allocate new
> 3) if 2) succeed, attach new otherwise attach old
The implementation is now:
1. allocate new
2. free old (detach old)
3. attach new
error:
1. free temporary
2. reinit old
Do you think this is ok? We need to add a new variable to save the old vring in
the process you mentioned, there is not much difference in other.
Thanks.
>
> This seems more clearer than the current logic?
>
> Thanks
>
>
> > + return -ENOMEM;
> > +}
> > +
> >
> > /*
> > * Generic functions and exported symbols.
>
next prev parent reply other threads:[~2022-07-04 2:20 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-29 6:56 [PATCH v11 00/40] virtio pci support VIRTIO_F_RING_RESET Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 01/40] virtio: add helper virtqueue_get_vring_max_size() Xuan Zhuo
2022-06-30 6:35 ` Jason Wang
2022-07-01 6:43 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 02/40] virtio: struct virtio_config_ops add callbacks for queue_reset Xuan Zhuo
2022-06-30 6:39 ` Jason Wang
2022-07-01 6:28 ` Michael S. Tsirkin
2022-07-01 6:42 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 03/40] virtio_ring: update the document of the virtqueue_detach_unused_buf for queue reset Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 04/40] virtio_ring: extract the logic of freeing vring Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 05/40] virtio_ring: split vring_virtqueue Xuan Zhuo
2022-06-30 6:40 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 06/40] virtio_ring: introduce virtqueue_init() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 07/40] virtio_ring: split: introduce vring_free_split() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 08/40] virtio_ring: split: extract the logic of alloc queue Xuan Zhuo
2022-07-01 8:26 ` Jason Wang
2022-07-01 8:45 ` Xuan Zhuo
2022-07-04 3:59 ` Jason Wang
2022-07-05 2:12 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 09/40] virtio_ring: split: extract the logic of alloc state and extra Xuan Zhuo
2022-07-01 8:55 ` Jason Wang
2022-07-04 2:04 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 10/40] virtio_ring: split: extract the logic of attach vring Xuan Zhuo
2022-07-01 9:00 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 11/40] virtio_ring: split: extract the logic of vring init Xuan Zhuo
2022-07-01 9:00 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 12/40] virtio_ring: split: introduce virtqueue_reinit_split() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 13/40] virtio_ring: split: reserve vring_align, may_reduce_num Xuan Zhuo
2022-07-01 9:03 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 14/40] virtio_ring: split: introduce virtqueue_resize_split() Xuan Zhuo
2022-07-01 9:09 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 15/40] virtio_ring: packed: introduce vring_free_packed Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 16/40] virtio_ring: packed: extract the logic of alloc queue Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 17/40] virtio_ring: packed: extract the logic of alloc state and extra Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 18/40] virtio_ring: packed: extract the logic of attach vring Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 19/40] virtio_ring: packed: extract the logic of vring init Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 20/40] virtio_ring: packed: introduce virtqueue_reinit_packed() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 21/40] virtio_ring: packed: introduce virtqueue_resize_packed() Xuan Zhuo
2022-07-01 9:27 ` Jason Wang
2022-07-04 2:13 ` Xuan Zhuo [this message]
2022-07-04 4:02 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 22/40] virtio_ring: introduce virtqueue_resize() Xuan Zhuo
2022-07-01 9:31 ` Jason Wang
2022-07-04 2:20 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 23/40] virtio_pci: move struct virtio_pci_common_cfg to virtio_pci_modern.h Xuan Zhuo
2022-07-01 9:33 ` Jason Wang
2022-07-04 2:23 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 24/40] virtio_pci: struct virtio_pci_common_cfg add queue_notify_data Xuan Zhuo
2022-07-01 9:34 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 25/40] virtio: allow to unbreak/break virtqueue individually Xuan Zhuo
2022-07-01 6:31 ` Michael S. Tsirkin
2022-07-01 9:36 ` Jason Wang
2022-07-04 3:47 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 26/40] virtio: queue_reset: add VIRTIO_F_RING_RESET Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 27/40] virtio_pci: struct virtio_pci_common_cfg add queue_reset Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 28/40] virtio_pci: introduce helper to get/set queue reset Xuan Zhuo
2022-07-01 9:39 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 29/40] virtio_pci: extract the logic of active vq for modern pci Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 30/40] virtio_pci: support VIRTIO_F_RING_RESET Xuan Zhuo
2022-07-04 3:27 ` Jason Wang
2022-06-29 6:56 ` [PATCH v11 31/40] virtio: find_vqs() add arg sizes Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 32/40] virtio_pci: support the arg sizes of find_vqs() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 33/40] virtio_mmio: " Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 34/40] virtio: add helper virtio_find_vqs_ctx_size() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 35/40] virtio_net: set the default max ring size by find_vqs() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 36/40] virtio_net: get ringparam by virtqueue_get_vring_max_size() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 37/40] virtio_net: split free_unused_bufs() Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 38/40] virtio_net: support rx queue resize Xuan Zhuo
2022-07-04 3:44 ` Jason Wang
2022-07-05 1:59 ` Xuan Zhuo
2022-07-08 6:20 ` Jason Wang
2022-07-15 8:36 ` Xuan Zhuo
2022-07-18 8:56 ` Jason Wang
2022-07-18 8:58 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 39/40] virtio_net: support tx " Xuan Zhuo
2022-07-04 3:45 ` Jason Wang
2022-07-05 2:00 ` Xuan Zhuo
2022-07-08 6:23 ` Jason Wang
2022-07-15 8:28 ` Xuan Zhuo
2022-07-18 8:57 ` Jason Wang
2022-07-18 9:11 ` Xuan Zhuo
2022-06-29 6:56 ` [PATCH v11 40/40] virtio_net: support set_ringparam Xuan Zhuo
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