APPLIED: [LP 1851709] Cannot launch KVM guests if EPT is disabled

[Thadeu Lima de Souza Cascardo]

On Tue, Nov 12, 2019 at 02:00:45PM +0100, Thomas Lamprecht wrote:
> On 11/12/19 11:32 AM, Stefan Bader wrote:
> > On 12.11.19 10:16, Thadeu Lima de Souza Cascardo wrote:
> >> It has been reported as failure to launch 64-bit linux VMs when kvm-intel
> >> ept module parameter is off. It is off by default on old Intel CPUs.
> >>
> >> The bionic revert has been tested as works fine. kvm-unit-tests has been
> >> run there as well and no regressions found.
> >>
> >>
> >>
> > Applied to disco+bionic/master-next. Thanks.
> > 
> 
> Why did you go the revert route and not the "backport the missing
> pieces"[0] one? For Disco cherry-picking upstream commit
> bf03d4f9334728bf7c8ffc7de787df48abd6340e is enough (tested here).  For
> disco the backport for 4.14[0] should be a working (did not tested yet).
> The patch which made problem show up was not a issue itself, and a valid
> fix, older kernel just missed some supporting fix, i.e., [0]. So, FWIWW,
> IMO it would be better to backport that instead of reverting.
> 
> cheers,
> Thomas
> 
> [0]: https://lore.kernel.org/stable/20191111233718.28438-1-sean.j.christopherson@intel.com/T/

Reverting was considered the safest option at the time we decided to fix
this regression in time for releases today.

In fact, the backport had not been sent by Sean yet at the time, and,
though we have already noticed the message where it was explained what
needed to be backported, we still considered it safer to revert.

The revert of the revert followed by the fix backport will probably follow
in a future release.

Hope that explains the situation.
Cascardo.

> 
> 
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