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Thu, 28 Jan 2021 03:12:02 +0000 (UTC) Received: from [10.72.12.167] (ovpn-12-167.pek2.redhat.com [10.72.12.167]) by smtp.corp.redhat.com (Postfix) with ESMTP id 649365D9E3; Thu, 28 Jan 2021 03:11:51 +0000 (UTC) Subject: Re: [RFC v3 03/11] vdpa: Remove the restriction that only supports virtio-net devices To: Stefano Garzarella Cc: Xie Yongji , mst@redhat.com, stefanha@redhat.com, parav@nvidia.com, bob.liu@oracle.com, hch@infradead.org, rdunlap@infradead.org, willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org References: <20210119045920.447-1-xieyongji@bytedance.com> <20210119045920.447-4-xieyongji@bytedance.com> <310d7793-e4ff-fba3-f358-418cb64c7988@redhat.com> <20210120110832.oijcmywq7pf7psg3@steredhat> <1979cffc-240e-a9f9-b0ab-84a1f82ac81e@redhat.com> <20210127085728.j6x5yzrldp2wp55c@steredhat> From: Jason Wang Message-ID: <3cb239f5-fdd5-8311-35a0-c0f50b552521@redhat.com> Date: Thu, 28 Jan 2021 11:11:49 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210127085728.j6x5yzrldp2wp55c@steredhat> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2021/1/27 下午4:57, Stefano Garzarella wrote: > On Wed, Jan 27, 2021 at 11:33:03AM +0800, Jason Wang wrote: >> >> On 2021/1/20 下午7:08, Stefano Garzarella wrote: >>> On Wed, Jan 20, 2021 at 11:46:38AM +0800, Jason Wang wrote: >>>> >>>> On 2021/1/19 下午12:59, Xie Yongji wrote: >>>>> With VDUSE, we should be able to support all kinds of virtio devices. >>>>> >>>>> Signed-off-by: Xie Yongji >>>>> --- >>>>>  drivers/vhost/vdpa.c | 29 +++-------------------------- >>>>>  1 file changed, 3 insertions(+), 26 deletions(-) >>>>> >>>>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >>>>> index 29ed4173f04e..448be7875b6d 100644 >>>>> --- a/drivers/vhost/vdpa.c >>>>> +++ b/drivers/vhost/vdpa.c >>>>> @@ -22,6 +22,7 @@ >>>>>  #include >>>>>  #include >>>>>  #include >>>>> +#include >>>>>  #include "vhost.h" >>>>> @@ -185,26 +186,6 @@ static long vhost_vdpa_set_status(struct >>>>> vhost_vdpa *v, u8 __user *statusp) >>>>>      return 0; >>>>>  } >>>>> -static int vhost_vdpa_config_validate(struct vhost_vdpa *v, >>>>> -                      struct vhost_vdpa_config *c) >>>>> -{ >>>>> -    long size = 0; >>>>> - >>>>> -    switch (v->virtio_id) { >>>>> -    case VIRTIO_ID_NET: >>>>> -        size = sizeof(struct virtio_net_config); >>>>> -        break; >>>>> -    } >>>>> - >>>>> -    if (c->len == 0) >>>>> -        return -EINVAL; >>>>> - >>>>> -    if (c->len > size - c->off) >>>>> -        return -E2BIG; >>>>> - >>>>> -    return 0; >>>>> -} >>>> >>>> >>>> I think we should use a separate patch for this. >>> >>> For the vdpa-blk simulator I had the same issues and I'm adding a >>> .get_config_size() callback to vdpa devices. >>> >>> Do you think make sense or is better to remove this check in >>> vhost/vdpa, delegating the boundaries checks to >>> get_config/set_config callbacks. >> >> >> A question here. How much value could we gain from get_config_size() >> consider we can let vDPA parent to validate the length in its >> get_config(). >> > > I agree, most of the implementations already validate the length, the > only gain is an error returned since get_config() is void, but > eventually we can add a return value to it. Right, one problem here is that. For the virito path, its get_config() returns void. So we can not propagate error to virtio drivers. But it might not be a big issue since we trust kernel virtio driver. So I think it makes sense to change the return value in the vdpa config ops. Thanks > > Thanks, > Stefano >