<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p><br>
</p>
<div class="moz-cite-prefix">On 10/07/19 9:22 AM, Michael Neuling
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:c395d650596905c118afed2b05fe9d62c69771ea.camel@neuling.org">
<pre class="moz-quote-pre" wrap="">On Tue, 2019-07-09 at 20:53 +0530, Vasant Hegde wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">On 07/09/2019 03:33 PM, Oliver O'Halloran wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">On Sun, 2019-06-16 at 22:40 +0530, Vasant Hegde wrote:
</pre>
</blockquote>
</blockquote>
</blockquote>
<pre>[...]</pre>
<blockquote type="cite"
cite="mid:c395d650596905c118afed2b05fe9d62c69771ea.camel@neuling.org">
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">
OS won't guess anything about firmware memory usage. In fact it won't care
about
firmware memory except `fw-load-area`.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">We already communicate some of that
information via the fw-load-area DT property, but that only contains the
ranges where skiboot loads the kernel and initrd (0x2000_000...0x2fff_ffff).
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
OS needs to know about these memory ranges *only*...as first kernel may use
these
memory. If it uses it should take care of reserving destination memory to
preserve these
memory and pass it during MPIPL registration.
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Odds are hostboot doesn't use *that* much memory, but the petitboot kernel
can
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
As mentioned above kernel need not worry about hostboot memory usage...as its
part of reserved-memory ranges.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
Vasant,
I think you may have missed Oliver's point in the above.
The Petitboot kernel needs some amount space to operate. In your current patch
series, the amount of space "firmware" is allowed to use is hard-wired by the
crashing kernel. Olivers point is that this size should be defined dynamically
by firmware, not hard-wired into the crashing kernel.
If we every change petitboot or some other component of the firmware so that it
needs to use more memory, then the crashing kernel won't have any way of
discovering that and it won't allocate enough space for this process to start.
</pre>
</blockquote>
<pre>
Mikey, the memory to be used by petitboot kernel is restricted by crashkernel parameter.
This is not hard-wired. This has to be configured by the user (a systemadmin, generally).
The value is typically something that has to be sufficient to boot a petitboot kernel and
also the production kernel to capture the dump...
Thanks
Hari
</pre>
</body>
</html>