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From: liu ping fan <qemulist@gmail.com>
Date: Tue, 23 Oct 2012 13:52:32 +0800
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Subject: Re: [Qemu-devel] [patch v4 13/16] e1000: add busy flag to anti
 broken device state
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To: Avi Kivity <avi@redhat.com>
Cc: Liu Ping Fan <pingfank@linux.vnet.ibm.com>, Stefan Hajnoczi <stefanha@gmail.com>, Marcelo Tosatti <mtosatti@redhat.com>, qemu-devel@nongnu.org, Anthony Liguori <anthony@codemonkey.ws>, Jan Kiszka <jan.kiszka@siemens.com>, Paolo Bonzini <pbonzini@redhat.com>

On Mon, Oct 22, 2012 at 6:40 PM, Avi Kivity <avi@redhat.com> wrote:
> On 10/22/2012 11:23 AM, Liu Ping Fan wrote:
>> The broken device state is caused by releasing local lock before acquiring
>> big lock. To fix this issue, we have two choice:
>>   1.use busy flag to protect the state
>>     The drawback is that we will introduce independent busy flag for each
>>     independent device's logic unit.
>>   2.reload the device's state
>>     The drawback is if the call chain is too deep, the action to reload will
>>     touch each layer. Also the reloading means to recaculate the intermediate
>>     result based on device's regs.
>>
>> This patch adopt the solution 1 to fix the issue.
>
> Doesn't the nested mmio patch detect this?
>
It will only record and fix the issue on one thread. But guest can
touch the emulated device on muti-threads.
>
> --
> error compiling committee.c: too many arguments to function
>