From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 1/3] virtio: Basic implementation of virtio pstore driver
Date: Fri, 18 Nov 2016 10:45:12 +0100
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To: Namhyung Kim <namhyung@kernel.org>
Cc: virtio-dev@lists.oasis-open.org, Tony Luck <tony.luck@intel.com>, Kees Cook <keescook@chromium.org>, KVM <kvm@vger.kernel.org>, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, LKML <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>, qemu-devel <qemu-devel@nongnu.org>, Minchan Kim <minchan@kernel.org>, Anton Vorontsov <anton@enomsg.org>, Anthony Liguori <aliguori@amazon.com>, Colin Cross <ccross@android.com>, virtualization@lists.linux-foundation.org, Ingo Molnar <mingo@kernel.org>
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On 18/11/2016 04:32, Namhyung Kim wrote:
>> In addition, the firmware will need to reserve a few KB of RAM for the error log
>> address range (I checked a real system and it reserves 8KB).  The first eight
>> bytes are needed for the record identifier interface, because there's no such
>> thing as 64-bit I/O ports, and the rest can be used for the actual buffer.
> 
> Is there a limit on the size?  It'd be great if it can use a few MB..

Yes, you can make it customizable.

>>> Also I need to control pstore driver like using bigger buffer,
>>> enabling specific message types and so on if ERST supports.  Is it
>>> possible for ERST to provide such information?
>>
>> It's the normal pstore driver, same as on a real server.  What exactly do you
>> need?
> 
> Well, I don't want to send additional pstore messages to the device if
> it cannot handle them properly - for example, ftrace message should not
> overwrite kmsg dump.  It'd be great if device somehow could expose
> acceptable message types to the driver IMHO.

This is something that you have to do in the usual kernel pstore
infrastructure.  It should not be specific to virtualization.

Paolo

> Btw I prefer using the kvmtool for my kernel work since it's much more
> simpler..