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Re: [Xen-devel] libxc: correctly unmap pages after core-dumping a pv gue

To: Markus Groß <gross@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] libxc: correctly unmap pages after core-dumping a pv guest
From: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Date: Tue, 24 May 2011 16:07:03 +0100
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Markus Groß writes ("[Xen-devel] libxc: correctly unmap pages after 
core-dumping a pv guest"):
> But to unmap the pages later, the dinfo->p2m_size has to be set accordingly.
> This was not done, instead a variable named p2m_size was set.
> This way P2M_FL_ENTRIES was always zero and the pages were left mapped.
> The following patch fixes this.

Thanks.  The existing code here is pretty unfortunate.

In xc_domain_dumpcore_via_callback where you make your change, "dinfo"
refers to a struct domain_info_context which is local to that
function.  But in the called function xc_core_arch_map_p2m_rw, "dinfo"
refers to another identical structure allocated locally to the small
wrapper function xc_core_arch_map_p2m.  All rather tangled.

But, anyway, your change is correct so I have applied it.

Next time, though, can you please be sure to add a Signed-off-by line,
to signify your certification in accordance with the Developer's
Certificate of Origin ?  In this case I'll go ahead as it's only a
couple of lines.


>From Documentation/SubmittingPatches in the Linux kernel tree:
        Developer's Certificate of Origin 1.1
        By making a contribution to this project, I certify that:
        (a) The contribution was created in whole or in part by me and I
            have the right to submit it under the open source license
            indicated in the file; or
        (b) The contribution is based upon previous work that, to the best
            of my knowledge, is covered under an appropriate open source
            license and I have the right under that license to submit that
            work with modifications, whether created in whole or in part
            by me, under the same open source license (unless I am
            permitted to submit under a different license), as indicated
            in the file; or
        (c) The contribution was provided directly to me by some other
            person who certified (a), (b) or (c) and I have not modified
        (d) I understand and agree that this project and the contribution
            are public and that a record of the contribution (including all
            personal information I submit with it, including my sign-off) is
            maintained indefinitely and may be redistributed consistent with
            this project or the open source license(s) involved.

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