[libvirt] [PATCH] libxl: always enable pae for x86_64 HVM

[Martin Kletzander]

On Thu, Jan 12, 2017 at 03:51:43PM +0100, Martin Kletzander wrote:
>On Thu, Jan 12, 2017 at 02:34:37PM +0000, Daniel P. Berrange wrote:
>>On Thu, Jan 12, 2017 at 07:31:29AM -0700, Jim Fehlig wrote:
>>> On 01/12/2017 02:06 AM, Martin Kletzander wrote:
>>> > On Wed, Jan 11, 2017 at 05:45:27PM -0700, Jim Fehlig wrote:
>>> > > For HVM domains, pae is only set in libxl_domain_build_info when
>>> > > explicitly specified in the hypervisor <features> config. This is
>>> > > fine for i686 machines, but is incorrect behavior for x86_64 machines
>>> > > where pae must always be enabled. See the following discussion for
>>> > > additional details
>>> > >
>>> > > https://www.redhat.com/archives/libvir-list/2017-January/msg00254.html
>>> > > Signed-off-by: Jim Fehlig <jfehlig at suse.com>
>>> > > ---
>>> > > src/libxl/libxl_domain.c | 6 ++++++
>>> > > 1 file changed, 6 insertions(+)
>>> > >
>>> > > diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
>>> > > index fbe7ee5..a5314b0 100644
>>> > > --- a/src/libxl/libxl_domain.c
>>> > > +++ b/src/libxl/libxl_domain.c
>>> > > @@ -410,6 +410,12 @@ libxlDomainDefPostParse(virDomainDefPtr def,
>>> > >     if (xenDomainDefAddImplicitInputDevice(def) < 0)
>>> > >         return -1;
>>> > >
>>> > > +    /* For x86_64 HVM, always enable pae */
>>> > > +    if (def->os.type == VIR_DOMAIN_OSTYPE_HVM &&
>>> > > +        def->os.arch == VIR_ARCH_X86_64) {
>>> > > +        def->features[VIR_DOMAIN_FEATURE_PAE] = VIR_TRISTATE_SWITCH_ON;
>>> > > +    }
>>> > > +
>>> >
>>> > This will even rewrite explicit <pae enabled='no/>
>>>
>>> According to docs/schemas/domaincommon.rng, pae is not a tristate :-). One
>>> of the options for solving this problem is to make it one
>>>
>>> https://www.redhat.com/archives/libvir-list/2017-January/msg00254.html
>>
>>Heh, the schema is wrong then, since the code treats all features
>>the same way, as tri-states :-)
>>
>
>It does not, pae is explicitly just:
>
>            <element name="pae">
>              <empty/>
>            </element>
>

I've hit 'send' too soon.  It does not, we just use virSwitchTristate
for saving the values, but it parses and formats them separately.

>Martin
>
>>Regards,
>>Daniel
>>--
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>>|: http://libvirt.org              -o-             http://virt-manager.org :|
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>>
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