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

[Jim Fehlig]

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

>
> I would check that it's not VIR_TRISTATE_SWITCH_OFF, then enable it and
> during startup just fail if it is VIR_TRISTATE_SWITCH_ON.

I suppose you mean fail if it is *not* VIR_TRISTATE_SWITCH_ON?

Regards,
Jim

>
>>     return 0;
>> }
>>
>> --
>> 2.9.2
>>
>> --
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