[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle
From: |
Halil Pasic |
Subject: |
Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request |
Date: |
Wed, 17 May 2017 12:33:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 |
On 05/17/2017 12:13 PM, Gonglei (Arei) wrote:
>>
>> On 05/17/2017 11:12 AM, Gonglei (Arei) wrote:
>>>>>> By the way, I'm having a hard time understing how is the requirement
>> form
>>>>>>
>>>>
>> http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-260
>>>>>> 004
>>>>>> (2.4.4 Message Framing) satisfied by this code. Could you explain this
>>>>>> to me please?
>>>>>>
>>>>> Sorry for my bad English,
>>>>> I don't know which normative formulation the code violates?
>>>> I'm not sure it's actually violated, but I'm concerned about the following
>>>> normative statement: "The device MUST NOT make assumptions about the
>>>> particular
>>>> arrangement of descriptors. The device MAY have a reasonable limit of
>>>> descriptors it will allow in a chain."
>>>>
>>>> Please also read the explanatory part I've linked, because the normative
>>>> statement is pretty abstract.
>>>>
>>>> In my understanding, the spec says, that e.g. the virti-crypto device
>>>> should not fail if a single request is split up into let's say two chunks
>>>> and transmitted by the means of two top level descriptors.
>>>>
>>>> Do you agree with my reading of the spec?
>>>>
>>> Yes, I agree. But what's the relationship about the request here?
>>> We don't assume the request have to use one desc entity, it can
>>> use scatter-gather list for one request header.
>>> The device can cover the situation in the QEMU.
>>>
>>>> What does the virtio-crypto device do if it encounters such a situation?
>>>>
>>> This isn't a problem. Pls see blow code segment:
>>>
>>> virtio_crypto_handle_request()
>>> {...
>>> if (unlikely(iov_to_buf(out_iov, out_num, 0, &req, sizeof(req))
>>> != sizeof(req))) {
>>> virtio_error(vdev, "virtio-crypto request outhdr too short");
>>> return -1;
>>> }
>>> iov_discard_front(&out_iov, &out_num, sizeof(req));
>>> ...
>>>
>>
>> Thats exactly what worries me. I see a call to virtio_error there...
>>
>>
>> void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt,
>> ...)
>> {
>> va_list ap;
>>
>> va_start(ap, fmt);
>> error_vreport(fmt, ap);
>> va_end(ap);
>>
>> vdev->broken = true;
>>
>> if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
>> virtio_set_status(vdev, vdev->status |
>> VIRTIO_CONFIG_S_NEEDS_RESET);
>> virtio_notify_config(vdev);
>> }
>> }
>>
>> This however seems to make the device 'broken'. Or am I missing something?
>>
> Yes, if the parse process failed, the device will broke.
> But This is a exception scenario IMHO, which is the same situation
> with other virtio devices.
I know that virtio-blk does the same. I'm not sure my reading of the
spec is correct. Maybe Stefan, Michael or Connie can clarify this
for us!
By the way for virtio-blk the current handling was introduced by
commit 20ea686a0 (by Greg Kurz), but before we were failing even harder.
Regards,
Halil
>
> Stefan introduced the virtio_error().
>
> Thanks,
> -Gonglei
>
- [Qemu-devel] [RFC v1 0/9] virtio-crypto: add stateless mode support, Gonglei, 2017/05/08
- [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei, 2017/05/08
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/12
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei (Arei), 2017/05/12
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/15
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei (Arei), 2017/05/15
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/16
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei (Arei), 2017/05/17
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/17
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei (Arei), 2017/05/17
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request,
Halil Pasic <=
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Cornelia Huck, 2017/05/17
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/17
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/18
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Gonglei (Arei), 2017/05/18
- Re: [Qemu-devel] [RFC v1 6/9] virtio-crypto: rework virtio_crypto_handle_request, Halil Pasic, 2017/05/29
[Qemu-devel] [RFC v1 5/9] virtio-crypto: update header file, Gonglei, 2017/05/08
[Qemu-devel] [RFC v1 3/9] cryptodev: add missing op_code for symmertric crypto, Gonglei, 2017/05/08
[Qemu-devel] [RFC v1 9/9] qtest: emulate virtio crypto as a legacy device for experiment, Gonglei, 2017/05/08