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Subject: Re: [PATCH 1/2] pvpanic: introduce crashloaded for pvpanic
To:     Markus Armbruster <armbru@redhat.com>,
        zhenwei pi <pizhenwei@bytedance.com>
Cc:     yelu@bytedance.com, libvir-list@redhat.com,
        gregkh@linuxfoundation.org, qemu-devel@nongnu.org,
        linux-kernel@vger.kernel.org, mprivozn@redhat.com
References: <20200110100634.491936-1-pizhenwei@bytedance.com>
 <20200110100634.491936-2-pizhenwei@bytedance.com>
 <87h80pi5hf.fsf@dusky.pond.sub.org>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <247586dd-576a-a0c9-9c43-5d9a310a4ddc@redhat.com>
Date:   Tue, 21 Jan 2020 11:50:53 +0100
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On 21/01/20 09:22, Markus Armbruster wrote:
> zhenwei pi <pizhenwei@bytedance.com> writes:
> 
>> Add bit 1 for pvpanic. This bit means that guest hits a panic, but
>> guest wants to handle error by itself. Typical case: Linux guest runs
>> kdump in panic. It will help us to separate the abnormal reboot from
>> normal operation.
>>
>> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
>> ---
>>  docs/specs/pvpanic.txt | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/specs/pvpanic.txt b/docs/specs/pvpanic.txt
>> index c7bbacc778..bdea68a430 100644
>> --- a/docs/specs/pvpanic.txt
>> +++ b/docs/specs/pvpanic.txt
>> @@ -16,8 +16,12 @@ pvpanic exposes a single I/O port, by default 0x505. On read, the bits
>>  recognized by the device are set. Software should ignore bits it doesn't
>>  recognize. On write, the bits not recognized by the device are ignored.
>>  Software should set only bits both itself and the device recognize.
> 
> Guest software, I presume.
> 
>> -Currently, only bit 0 is recognized, setting it indicates a guest panic
>> -has happened.
>> +
>> +Bit Definition
>> +--------------
>> +bit 0: setting it indicates a guest panic has happened.
>> +bit 1: named crashloaded. setting it indicates a guest panic and run
>> +       kexec to handle error by guest itself.
> 
> Suggest to scratch "named crashloaded."

bit 1: a guest panic has happened and will be handled by the guest;
       the host should record it or report it, but should not affect
       the execution of the guest.

?

Paolo