Re: [edk2-devel] [PATCH v2 00/16] OvmfPkg: support VCPU hotplug with -D SMM_REQUIRE

["Laszlo Ersek" <lersek@redhat.com>]

On 02/26/20 23:11, Laszlo Ersek wrote:
> Supersedes: <20200223172537.28464-1-lersek@redhat.com>
> Bugzilla:   https://bugzilla.tianocore.org/show_bug.cgi?id=1512
> Repo:       https://github.com/lersek/edk2.git
> Branch:     vcpu_hotplug_smm_bz_1512_v2
> 
> V1 was posted at:
> 
> * [edk2-devel] [PATCH 00/16]
>   OvmfPkg: support VCPU hotplug with -D SMM_REQUIRE
> 
>   https://edk2.groups.io/g/devel/message/54734
>   http://mid.mail-archive.com/20200223172537.28464-1-lersek@redhat.com
> 
> New in v2:
> 
> - Document (in patch#11) and implement (in patch#12) the "combined"
>   approach described here:
> 
>   http://mid.mail-archive.com/111145fc-be3d-2a9a-a126-c14345a8a8a4@redhat.com
>   https://edk2.groups.io/g/devel/message/54754
> 
>   The idea is basically to make the SMM Monarch wait not just until the
>   hot-added CPU hits the normal RAM Post-SMM Pen (which is safe wrt.
>   ordering, but can be attacked by the OS), but *also* until the
>   hot-added CPU is just about to execute RSM first (which is a bit less
>   safe wrt. ordering, but cannot be attacked by the OS).
> 
> - Pick up Ard's conditional A-b for the other patches, which have not
>   been modified.
> 
> - Rebase to master, and retest.

Thanks everyone for the feedback!

I plan to push this series soon after the hard feature freeze ends, and
edk2-stable202002 is tagged. I have three questions / remarks regarding
that:

- Phil, please tell me if you'd like me to hold the series for longer.
(You seem to have reached the end of the series, and I'm unsure about
the skipped patches -- maybe you want to skip them, maybe you need more
time for them.)

- I've talked to Igor about ordering the merging of the firmware set vs.
the merging of the QEMU patches. Igor made the great point that in this
case, QEMU is the user / consumer (ACPI payload) of the firmware
feature, and so the firmware stuff should go in first. I hadn't thought
of that, but he convinced me. The QEMU PoC patch is available, Boris has
tested the patches against each other, and this OVMF set in itself does
not regress anything functional. (Note that, while several patches in
the series *do* affect code paths that are independent of CPU hotplug, I
also regression-tested those.)

- Once the set is "in", I'll mark TianoCore#1512 as one of the new
features (for the first stable tag *after* edk2-stable202002) at
<https://github.com/tianocore/tianocore.github.io/wiki/EDK-II-Release-Planning>.

Thanks
Laszlo