[Merge] ~rafaeldtinoco/ubuntu/+source/qemu:lp1828495-disco-devel-qemu into ubuntu/+source/qemu:ubuntu/disco-devel

[Rafael David Tinoco]

Based on public bug feedback from Intel, looks like I've missed the undocumented MDS-NO mitigation bit from ARCH_CAPABILITIES. I haven't done it because last manual from Intel does not show it, I'm really not sure where to find more documentation about it.. but its a simple upstream change (just the MSR flag) so I backported and I'm pushing the change here.

I'm first dealing with the Bionic SRU, and if it is all good, I'll include the same patch in this change. 

Comments from the Bionic merge request:

https://code.launchpad.net/~rafaeldtinoco/ubuntu/+source/qemu/+git/qemu/+merge/368804/comments/969879
https://code.launchpad.net/~rafaeldtinoco/ubuntu/+source/qemu/+git/qemu/+merge/368804/comments/969880

>From the other merge request:

"""
This is the upstream change:

https://github.com/qemu/qemu/commit/20140a82c674

This is the public comment from Intel:

https://bugs.launchpad.net/intel/+bug/1828495/comments/40

And commit the patch is:

    - 0017-target-i386-add-MDS-NO-feature.patch (LP: #1828495):
      target/i386: add MDS-NO feature
      (upstream: 20140a82c674, desc: v4.0.0-721-g20140a82c6)
"""
-- 
https://code.launchpad.net/~rafaeldtinoco/ubuntu/+source/qemu/+git/qemu/+merge/369470
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~rafaeldtinoco/ubuntu/+source/qemu:lp1828495-disco-devel-qemu into ubuntu/+source/qemu:ubuntu/disco-devel.