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Re: [PATCH v3 07/16] libqos: enforce Device Initialization order
From: |
Thomas Huth |
Subject: |
Re: [PATCH v3 07/16] libqos: enforce Device Initialization order |
Date: |
Tue, 22 Oct 2019 20:48:31 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
On 22/10/2019 17.48, Stefan Hajnoczi wrote:
> On Mon, Oct 21, 2019 at 02:15:53PM +0200, Thomas Huth wrote:
>> On 19/10/2019 08.38, Stefan Hajnoczi wrote:
>>> According to VIRTIO 1.1 "3.1.1 Driver Requirements: Device
>>> Initialization", configuration space and virtqueues cannot be accessed
>>> before features have been negotiated. Enforce this requirement.
>>>
>>> Signed-off-by: Stefan Hajnoczi <address@hidden>
>>> ---
>>> tests/libqos/virtio.c | 11 +++++++++++
>>> 1 file changed, 11 insertions(+)
>>>
>>> diff --git a/tests/libqos/virtio.c b/tests/libqos/virtio.c
>>> index 4f7e6bb8a1..2593996c98 100644
>>> --- a/tests/libqos/virtio.c
>>> +++ b/tests/libqos/virtio.c
>>> @@ -13,23 +13,33 @@
>>> #include "standard-headers/linux/virtio_config.h"
>>> #include "standard-headers/linux/virtio_ring.h"
>>>
>>> +/* Features must be negotiated before config space or virtqueue access */
>>> +static void check_features_negotiated(QVirtioDevice *d)
>>> +{
>>> + g_assert_cmphex(d->features, !=, 0);
>>> +}
>>
>> Isn't it "legal" to negotiate 0 feature bits, too (for legacy devices)?
>
> Yes, it's possible for Legacy devices. If someone ever does that
> they'll need to extend this code, but it's unlikely so I'd rather not
> complicate this.
Could you please add at least a comment here with that explanation?
Thanks,
Thomas
- [PATCH v3 04/16] virtio-scsi-test: add missing feature negotiation, (continued)
[PATCH v3 08/16] libqos: implement VIRTIO 1.0 FEATURES_OK step, Stefan Hajnoczi, 2019/10/19
[PATCH v3 09/16] libqos: access VIRTIO 1.0 vring in little-endian, Stefan Hajnoczi, 2019/10/19
[PATCH v3 10/16] libqos: add iteration support to qpci_find_capability(), Stefan Hajnoczi, 2019/10/19