Bug 222467 - [XEN-VT]'Cannot allocate memory' error
[XEN-VT]'Cannot allocate memory' error
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: xen (Show other bugs)
All Linux
high Severity high
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Assigned To: Xen Maintainance List
Depends On: 217056
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Reported: 2007-01-12 12:45 EST by Steven Rostedt
Modified: 2007-11-30 17:07 EST (History)
6 users (show)

See Also:
Fixed In Version: 5.0.0
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2007-02-14 11:32:04 EST
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RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
Enable shadow before memory reservation for HVM (3.44 KB, patch)
2007-01-27 00:17 EST, Herbert Xu
no flags Details | Diff
[XEN]: Enable shadow before memory reservation for HVM (5.28 KB, patch)
2007-01-28 05:57 EST, Herbert Xu
no flags Details | Diff

  None (edit)
Comment 1 Herbert Xu 2007-01-27 00:17:32 EST
Created attachment 146739 [details]
Enable shadow before memory reservation for HVM

It turns out that the bogus m2p entries are a recent introduction.  When
shadow2 (changeset 11151) was introduced, upstream moved the code that enables
shadow mode for HVM guests to user-space.  In particular, this was done after
memory allocation and before the physmap has been populated.  This only
affected HVM because PV translate mode populated the physmap before enabling
shadow mode.

Upstream has since fixed it by moving the enabling of shadow mode back into the
hypervisor which means that it will occur before memory allocation.  This patch
tries to do this in a more conservative way by simply moving the enabling of
shadow mode before memory allocation.

I've verified that running this version of xend allows me to start HVM guests
on a host where otherwise you can't start HVM guests at all due to this bug.

When we move to 3.0.4 we can remove the shadow_enable function from the python
bindings of libxc.
Comment 2 Herbert Xu 2007-01-28 05:57:35 EST
Created attachment 146761 [details]
[XEN]: Enable shadow before memory reservation for HVM

This version adds an HVM check so that we only enable shadow mode on HVM
guests.  The shadow_enable function is also renamed to hvm_shadow_enable.
Comment 5 Jay Turner 2007-01-29 15:45:20 EST
QE ack for RHEL5.
Comment 6 Brian Stein 2007-01-29 15:47:37 EST
Rik - Let's build the pacakge and the version number in the BZ.  If we decide to
include it in a respin, we can drag it in.

Comment 8 Rik van Riel 2007-02-01 17:18:34 EST
in 3.0.3-23.el5
Comment 10 Jay Turner 2007-02-14 11:32:04 EST
Closing out.

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