https://linux-kvm.org/index.php?title=Nested_Guests&feed=atom&action=history
Nested Guests - Revision history
2024-03-29T00:54:52Z
Revision history for this page on the wiki
MediaWiki 1.39.5
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173935&oldid=prev
Testemail: Undo revision 173934 by Testemail (talk)
2018-11-05T21:38:21Z
<p>Undo revision 173934 by <a href="/page/Special:Contributions/Testemail" title="Special:Contributions/Testemail">Testemail</a> (<a href="/index.php?title=User_talk:Testemail&action=edit&redlink=1" class="new" title="User talk:Testemail (page does not exist)">talk</a>)</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 17:38, 5 November 2018</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td></tr>
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Testemail
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173934&oldid=prev
Testemail: temp change to test the removal of link check script
2018-11-05T21:37:56Z
<p>temp change to test the removal of link check script</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 17:37, 5 November 2018</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td></tr>
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Testemail
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173900&oldid=prev
Fghaas: Add link to kernel.org bug 53851
2018-02-12T14:01:37Z
<p>Add link to kernel.org bug 53851</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:01, 12 February 2018</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.redhat.com/show_bug.cgi?id=1076294 Red Hat Bugzilla Bug 1076294 ]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.redhat.com/show_bug.cgi?id=1076294 Red Hat Bugzilla Bug 1076294 ]</div></td></tr>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.kernel.org/show_bug.cgi?id=198621 kernel.org Bugzilla Bug 198621]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.kernel.org/show_bug.cgi?id=198621 kernel.org Bugzilla Bug 198621]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</div></td></tr>
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Fghaas
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173899&oldid=prev
Kashyapc at 09:24, 12 February 2018
2018-02-12T09:24:45Z
<p></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:24, 12 February 2018</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l5">Line 5:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>When describing nested guests, we will use the following terminology:</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>When describing nested guests, we will use the following terminology:</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L0" <del style="font-weight: bold; text-decoration: none;">-- </del>the bare metal host, running KVM</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* "L0" <ins style="font-weight: bold; text-decoration: none;">– </ins>the bare metal host, running KVM</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L1" <del style="font-weight: bold; text-decoration: none;">-- </del>a VM running on L0; also called the "guest hypervisor" <del style="font-weight: bold; text-decoration: none;">-- </del>as it ''itself'' is capable of running KVM</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* "L1" <ins style="font-weight: bold; text-decoration: none;">– </ins>a VM running on L0; also called the "guest hypervisor" <ins style="font-weight: bold; text-decoration: none;">— </ins>as it ''itself'' is capable of running KVM</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L2" <del style="font-weight: bold; text-decoration: none;">-- </del>a VM running on L1, also called the "nested guest"</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* "L2" <ins style="font-weight: bold; text-decoration: none;">– </ins>a VM running on L1, also called the "nested guest"</div></td></tr>
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Kashyapc
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173898&oldid=prev
Kashyapc at 09:23, 12 February 2018
2018-02-12T09:23:30Z
<p></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>= Nested Guests =</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>= Nested Guests =</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Nested guests are KVM guests run in a KVM guest. As of 2018 this feature is considered working but experimental, and some limitations apply.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Nested guests are KVM guests run in a KVM guest. As of <ins style="font-weight: bold; text-decoration: none;">Feb </ins>2018 this feature is considered working but experimental, and some limitations apply.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>When describing nested guests, the following <del style="font-weight: bold; text-decoration: none;">conventions apply</del>:</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>When describing nested guests, <ins style="font-weight: bold; text-decoration: none;">we will use </ins>the following <ins style="font-weight: bold; text-decoration: none;">terminology</ins>:</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L0" <del style="font-weight: bold; text-decoration: none;">is an unvirtualized </del>host <del style="font-weight: bold; text-decoration: none;">system capable of </del>running KVM<del style="font-weight: bold; text-decoration: none;">.</del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins style="font-weight: bold; text-decoration: none;"> </ins>"L0" <ins style="font-weight: bold; text-decoration: none;">-- the bare metal </ins>host<ins style="font-weight: bold; text-decoration: none;">, </ins>running KVM</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L1" <del style="font-weight: bold; text-decoration: none;">is </del>a <del style="font-weight: bold; text-decoration: none;">virtual system </del>running on L0<del style="font-weight: bold; text-decoration: none;">, which is itself </del>''<del style="font-weight: bold; text-decoration: none;">also</del>'' capable of running KVM<del style="font-weight: bold; text-decoration: none;">.</del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins style="font-weight: bold; text-decoration: none;"> </ins>"L1" <ins style="font-weight: bold; text-decoration: none;">-- </ins>a <ins style="font-weight: bold; text-decoration: none;">VM </ins>running on L0<ins style="font-weight: bold; text-decoration: none;">; also called the "guest hypervisor" -- as it </ins>''<ins style="font-weight: bold; text-decoration: none;">itself</ins>'' <ins style="font-weight: bold; text-decoration: none;">is </ins>capable of running KVM</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* "L2" <del style="font-weight: bold; text-decoration: none;">is </del>a <del style="font-weight: bold; text-decoration: none;">virtual system </del>running on L1, <del style="font-weight: bold; text-decoration: none;">which does no further virtualization.</del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins style="font-weight: bold; text-decoration: none;"> </ins>"L2" <ins style="font-weight: bold; text-decoration: none;">-- </ins>a <ins style="font-weight: bold; text-decoration: none;">VM </ins>running on L1, <ins style="font-weight: bold; text-decoration: none;">also called the "nested guest"</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">In this context, we refer to L1 as an unnested guest, and L2 as a nested guest.</del></div></td><td colspan="2" class="diff-side-added"></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>= Detailed =</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>= Detailed =</div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l20">Line 20:</td>
<td colspan="2" class="diff-lineno">Line 19:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The KVM kernel modules do not enable nesting by default (though your distribution may override this default). To enable nesting, set the <code>nested</code> module parameter to <code>Y</code> or <code>1</code>. You may set this parameter persistently in a file in <code>/etc/modprobe.d</code> in the L0 host, for example:</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The KVM kernel modules do not enable nesting by default (though your distribution may override this default). To enable nesting, set the <code>nested</code> module parameter to <code>Y</code> or <code>1</code>. You may set this parameter persistently in a file in <code>/etc/modprobe.d</code> in the L0 host, for example:</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> # cat /etc/modprobe.d/kvm_intel.conf</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> # <ins style="font-weight: bold; text-decoration: none;">If you have an Intel CPU, use this:</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"> $ </ins>cat /etc/modprobe.d/kvm_intel.conf</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> options kvm-intel nested=Y</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> options kvm-intel nested=Y</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> # cat /etc/modprobe.d/kvm_amd.conf</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> # <ins style="font-weight: bold; text-decoration: none;">If you have an AMD CPU, then this:</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"> $ </ins>cat /etc/modprobe.d/kvm_amd.conf</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> options kvm-amd nested=1</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> options kvm-amd nested=1</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Once your L0 host is capable of nesting, you should be able to start an L1 guest with the <code>-cpu host</code> option, and the guest will subsequently be capable of running an L2 guest with accelerated KVM.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Once your L0 host is capable of nesting, you should be able to start an L1 guest with the <code>-cpu host</code> option <ins style="font-weight: bold; text-decoration: none;">(or for better live migration compatibility</ins>, <ins style="font-weight: bold; text-decoration: none;">use a named CPU model supported by QEMU, such as: <code>-cpu Haswell-noTSX-IBRS,vmx=on</code>) </ins>and the guest will subsequently be capable of running an L2 guest with accelerated KVM.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Limitations ==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Limitations ==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Once an L1 guest has started an L2 guest, it is no longer capable of being migrated, saved, or loaded (see [[Migration]] for details on these actions) until the L2 guest shuts down. This is currently an inherent limitation of the KVM implementation on all architectures except s390x.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Once an L1 guest has started an L2 guest, it is no longer capable of being migrated, saved, or loaded (see [[Migration]] for details on these actions) until the L2 guest shuts down. This is currently an inherent limitation <ins style="font-weight: bold; text-decoration: none;">(that is being worked on, as of Feb 2018) </ins>of the KVM implementation on all architectures except s390x.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Attempting to migrate or save & load an L1 guest while an L2 guest is running will result in undefined behavior. You might see a <code>kernel BUG!</code> entry in <code>dmesg</code>, a kernel oops, or an outright kernel panic. At any rate, a thus migrated or loaded L1 guest can no longer be considered stable or secure, and must be restarted.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Attempting to migrate or save & load an L1 guest while an L2 guest is running will result in undefined behavior. You might see a <code>kernel BUG!</code> entry in <code>dmesg</code>, a kernel oops, or an outright kernel panic. At any rate, a thus migrated or loaded L1 guest can no longer be considered stable or secure, and must be restarted.</div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l41">Line 41:</td>
<td colspan="2" class="diff-lineno">Line 42:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.redhat.com/show_bug.cgi?id=1076294 Red Hat Bugzilla Bug 1076294 ]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.redhat.com/show_bug.cgi?id=1076294 Red Hat Bugzilla Bug 1076294 ]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.kernel.org/show_bug.cgi?id=198621 kernel.org Bugzilla Bug 198621]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://bugzilla.kernel.org/show_bug.cgi?id=198621 kernel.org Bugzilla Bug 198621]</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/virtual/kvm/nested-vmx.txt Intel nVMX upstream specification]</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Docs]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Docs]]</div></td></tr>
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Kashyapc
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173896&oldid=prev
Fghaas: Fix title
2018-02-08T17:45:38Z
<p>Fix title</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 13:45, 8 February 2018</td>
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<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>= <del style="font-weight: bold; text-decoration: none;">Feature functional description </del>=</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>= <ins style="font-weight: bold; text-decoration: none;">Nested Guests </ins>=</div></td></tr>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Nested guests are KVM guests run in a KVM guest. As of 2018 this feature is considered working but experimental, and some limitations apply.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Nested guests are KVM guests run in a KVM guest. As of 2018 this feature is considered working but experimental, and some limitations apply.</div></td></tr>
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Fghaas
https://linux-kvm.org/index.php?title=Nested_Guests&diff=173893&oldid=prev
Fghaas: Add page on nested guests
2018-02-08T17:39:29Z
<p>Add page on nested guests</p>
<p><b>New page</b></p><div>= Feature functional description =<br />
<br />
Nested guests are KVM guests run in a KVM guest. As of 2018 this feature is considered working but experimental, and some limitations apply.<br />
<br />
When describing nested guests, the following conventions apply:<br />
<br />
* "L0" is an unvirtualized host system capable of running KVM.<br />
* "L1" is a virtual system running on L0, which is itself ''also'' capable of running KVM.<br />
* "L2" is a virtual system running on L1, which does no further virtualization.<br />
<br />
In this context, we refer to L1 as an unnested guest, and L2 as a nested guest.<br />
<br />
= Detailed =<br />
== Why use it? ==<br />
<br />
An additional layer of virtualization sometimes comes in handy. You might have access to a large virtual machine in a cloud environment that you want to compartmentalize into multiple workloads. You might be running a lab environment in a training session.<br />
<br />
== How to run ==<br />
<br />
The KVM kernel modules do not enable nesting by default (though your distribution may override this default). To enable nesting, set the <code>nested</code> module parameter to <code>Y</code> or <code>1</code>. You may set this parameter persistently in a file in <code>/etc/modprobe.d</code> in the L0 host, for example:<br />
<br />
# cat /etc/modprobe.d/kvm_intel.conf<br />
options kvm-intel nested=Y<br />
<br />
# cat /etc/modprobe.d/kvm_amd.conf<br />
options kvm-amd nested=1<br />
<br />
Once your L0 host is capable of nesting, you should be able to start an L1 guest with the <code>-cpu host</code> option, and the guest will subsequently be capable of running an L2 guest with accelerated KVM.<br />
<br />
<br />
== Limitations ==<br />
<br />
Once an L1 guest has started an L2 guest, it is no longer capable of being migrated, saved, or loaded (see [[Migration]] for details on these actions) until the L2 guest shuts down. This is currently an inherent limitation of the KVM implementation on all architectures except s390x.<br />
<br />
Attempting to migrate or save & load an L1 guest while an L2 guest is running will result in undefined behavior. You might see a <code>kernel BUG!</code> entry in <code>dmesg</code>, a kernel oops, or an outright kernel panic. At any rate, a thus migrated or loaded L1 guest can no longer be considered stable or secure, and must be restarted.<br />
<br />
Migrating an L1 guest merely ''configured to support'' nesting, while not ''actually'' running L2 guests, is expected to function normally. Live-migrating an L2 guest from one L1 guest to another is also expected to succeed.<br />
<br />
= Links =<br />
* [https://www.redhat.com/archives/libvirt-users/2018-February/msg00014.html Discussion on limitations of nested guests] (<code>libvirt-users</code> mailing list, February 2018)<br />
* [https://bugzilla.redhat.com/show_bug.cgi?id=1076294 Red Hat Bugzilla Bug 1076294 ]<br />
* [https://bugzilla.kernel.org/show_bug.cgi?id=198621 kernel.org Bugzilla Bug 198621]<br />
<br />
[[Category:Docs]]</div>
Fghaas