From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Liu <wei.liu2@citrix.com>
Subject: Re: [v7][PATCH 11/16] tools/libxl: detect and avoid
 conflicts with RDM
Date: Thu, 9 Jul 2015 10:11:51 +0100
Message-ID: <20150709091151.GB11671@zion.uk.xensource.com>
References: <1436420047-25356-1-git-send-email-tiejun.chen@intel.com>
	<1436420047-25356-12-git-send-email-tiejun.chen@intel.com>
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To: Tiejun Chen <tiejun.chen@intel.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, Ian Campbell <ian.campbell@citrix.com>, xen-devel@lists.xen.org
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On Thu, Jul 09, 2015 at 01:34:02PM +0800, Tiejun Chen wrote:
> While building a VM, HVM domain builder provides struct hvm_info_table{}
> to help hvmloader. Currently it includes two fields to construct guest
> e820 table by hvmloader, low_mem_pgend and high_mem_pgend. So we should
> check them to fix any conflict with RDM.
> 
> RMRR can reside in address space beyond 4G theoretically, but we never
> see this in real world. So in order to avoid breaking highmem layout
> we don't solve highmem conflict. Note this means highmem rmrr could still
> be supported if no conflict.
> 
> But in the case of lowmem, RMRR probably scatter the whole RAM space.
> Especially multiple RMRR entries would worsen this to lead a complicated
> memory layout. And then its hard to extend hvm_info_table{} to work
> hvmloader out. So here we're trying to figure out a simple solution to
> avoid breaking existing layout. So when a conflict occurs,
> 
>     #1. Above a predefined boundary (2G)
>         - move lowmem_end below reserved region to solve conflict;
> 
>     #2. Below a predefined boundary (2G)
>         - Check strict/relaxed policy.
>         "strict" policy leads to fail libxl. Note when both policies
>         are specified on a given region, 'strict' is always preferred.
>         "relaxed" policy issue a warning message and also mask this entry INVALID
>         to indicate we shouldn't expose this entry to hvmloader.
> 
> Note later we need to provide a parameter to set that predefined boundary
> dynamically.
> 
> CC: Ian Jackson <ian.jackson@eu.citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> CC: Ian Campbell <ian.campbell@citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
> Acked-by: Wei Liu <wei.liu2@citrix.com>
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> Reviewed-by: Kevin Tian <kevint.tian@intel.com>

Typo here "kevint"

No need to resend just for this though. I think committer can handle
this for you.

If you happen to resend because of changes in other patches, please
correct this.

Wei.