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From: Thomas Huth <thuth@redhat.com>
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Date: Fri, 20 Apr 2018 08:31:16 +0200
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Subject: Re: [Qemu-devel] [PATCH v1 for-2.13 2/4] pc-bios/s390-ccw/net: Stop
 virtio-net device before jumping into the OS
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To: Christian Borntraeger <borntraeger@de.ibm.com>, qemu-s390x@nongnu.org, Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>, qemu-devel@nongnu.org, Collin Walling <walling@linux.ibm.com>

On 19.04.2018 17:49, Christian Borntraeger wrote:
> On 04/18/2018 02:31 PM, Thomas Huth wrote:
>> The virtio-net receive buffers are filled asynchronously, so we should
>> make sure to properly shut down the virtio-net device before we jump into
>> the loaded kernel. Otherwise an incoming packet could destroy memory of
>> the OS kernel if it did not re-initialize the virtio-net device fast
>> enough yet.
> 
> The normal bios does a full subsystem reset before we enter the OS.
> (see jump_to_IPL_code the diag 308). That should reset all virtio 
> devices on the qemu level. Shouldnt we rather do the same for
> the net bios?

That should fix this issue, too, right. I'll give it a try and include
it in v2 if I can make it work...

 Thomas