Re: [Qemu-devel] [PATCH 1/3] virtio: Basic implementation of virtio pstore driver

[Paolo Bonzini]

On 15/11/2016 15:36, Namhyung Kim wrote:
> Hi,
> 
> On Tue, Nov 15, 2016 at 10:57:29AM +0100, Paolo Bonzini wrote:
>>
>>
>> On 15/11/2016 06:06, Michael S. Tsirkin wrote:
>>> On Tue, Nov 15, 2016 at 01:50:21PM +0900, Namhyung Kim wrote:
>>>> Hi Michael,
>>>>
>>>> On Thu, Nov 10, 2016 at 06:39:55PM +0200, Michael S. Tsirkin wrote:
>>>>> On Sat, Aug 20, 2016 at 05:07:42PM +0900, Namhyung Kim wrote:
>>>>>> The virtio pstore driver provides interface to the pstore subsystem so
>>>>>> that the guest kernel's log/dump message can be saved on the host
>>>>>> machine.  Users can access the log file directly on the host, or on the
>>>>>> guest at the next boot using pstore filesystem.  It currently deals with
>>>>>> kernel log (printk) buffer only, but we can extend it to have other
>>>>>> information (like ftrace dump) later.
>>>>>>
>>>>>> It supports legacy PCI device using single order-2 page buffer.
>>>>>
>>>>> Do you mean a legacy virtio device? I don't see why
>>>>> you would want to support pre-1.0 mode.
>>>>> If you drop that, you can drop all cpu_to_virtio things
>>>>> and just use __le accessors.
>>>>
>>>> I was thinking about the kvmtools which lacks 1.0 support AFAIK.
>>>
>>> Unless kvmtools wants to be left behind it has to go 1.0.
>>
>> And it also has to go ACPI.  Is there any reason, apart from kvmtool, to
>> make a completely new virtio device, with no support in existing guests,
>> rather than implement ACPI ERST?
> 
> Well, I know nothing about ACPI.  It looks like a huge spec and I
> don't want to dig into it just for this.

ERST (error record serialization table) is a small subset of the ACPI spec.

Paolo