Re: [Qemu-devel] [PATCH v4 0/7] q35: add negotiable broadcast SMI

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 10 Jan 2017 16:23:41 +0100
Laszlo Ersek <lersek@redhat.com> wrote:

> On 01/10/17 16:06, Michael S. Tsirkin wrote:
> > On Thu, Dec 01, 2016 at 06:06:17PM +0100, Laszlo Ersek wrote:
> >> * This is version 4 of the series; the last version was at
> >>   <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03582.html>.
> >>
> >>   This version is practically a rewrite from scratch, seeking to address
> >>   the v3 feedback. Here's what the individual patches do:
> >>
> >>   - Patch #1 rebases and extends Michael's "writeable fw_cfg blobs"
> >>     patch from Feb/March 2016. The changes relative to the original
> >>     patch are documented in the commit message (the code changes are
> >>     minimal).
> >>
> >>   - Patches #2 and #3 turn the FW_CFG_FILE_SLOTS constant into a device
> >>     property, and expose the desired number of fw_cfg file slots to
> >>     board code. This is meant to address a concern raised by Paolo in
> >>     the v2 review
> >>     <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03125.html>,
> >>     namely that we're about to run out of FW_CFG_FILE_SLOTS.
> >>
> >>   - Patch #4 introduces the "pc-q35-2.9" and "pc-i440fx-2.9" machine
> >>     types, which are allowed to take advantage of the new default for
> >>     fw_cfg file slots (0x20 rather than 0x10).
> >>
> >>   - Patch #5 introduces SMI feature negotiation via fw_cfg, with the
> >>     following new files:
> >>
> >>     - etc/smi/host-features
> >>     - etc/smi/guest-features
> >>     - etc/smi/features-ok
> >>
> >>     This is supposed to follow Michael's recommendation re: imitating
> >>     virtio
> >>     <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03218.html>.
> >>
> >>     The guest-features file is freely writeable by the guest (no write
> >>     callbacks in fw_cfg), and the feature validation & lockdown occurs
> >>     when the guest selects the features-ok file (for reading).
> >>
> >>     Board code is allowed to choose the host feature bitmap to
> >>     advertise.
> >>
> >>     This patch doesn't add any specific SMI features yet.
> >>
> >>   - Patch #6 adds the ICH9_LPC_SMI_F_BROADCAST feature.
> >>
> >>   - Patch #7 introduces the PCMachineClass.get_smi_host_features method,
> >>     and implements it for "pc-q35-2.9" and later. The idea is to tie the
> >>     SMI host features to machine types, and let the machine types
> >>     calculate their host features with code (i.e., not just a constant).
> >>
> >>     In this patch, the "pc-q35-2.9" machine type exposes the
> >>     ICH9_LPC_SMI_F_BROADCAST feature iff (smp_cpus == max_cpus), that
> >>     is, when VCPU hotplug is not possible. (Also from Paolo's v3
> >>     feedback, in
> >>     <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg04919.html>.)
> >>
> >> * I've written the OVMF side patches too and tested them together
> >>   (including gdb / debug messages for "white box" testing).
> >>
> >> * Note that this version depends on the following PULL req from Michael:
> >>
> >>   [Qemu-devel] [PULL 0/5] virtio, vhost, pc: fixes
> >>   http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg05503.html
> >>
> >>   In particular on the following patch:
> >>   "loader: fix handling of custom address spaces when adding ROM blobs"
> >>
> >> Cc: "Gabriel L. Somlo" <somlo@cmu.edu>
> >> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> >> Cc: Eduardo Habkost <ehabkost@redhat.com>
> >> Cc: Gerd Hoffmann <kraxel@redhat.com>
> >> Cc: Igor Mammedov <imammedo@redhat.com>
> >> Cc: Michael Walle <michael@walle.cc>
> >> Cc: Paolo Bonzini <pbonzini@redhat.com>
> >> Cc: Peter Maydell <peter.maydell@linaro.org>
> >> Cc: Shannon Zhao <zhaoshenglong@huawei.com>
> >> Cc: qemu-arm@nongnu.org
> >>
> >> Thanks
> >> Laszlo
> > 
> > So I reviewed fw cfg stuff, looks good to me.
> 
> Thank you.
> 
> I should note that Igor suggested / requested changes for patches #2 and
> #3; the sub-threads start at
> 
> http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00695.html
> msg-id: <20161206115038.4495a217@nial.brq.redhat.com>
> 
> http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00706.html
> msg-id: <20161206124906.76a41896@nial.brq.redhat.com>
> 
> I was about to rework the patches based on his feedback. Should we
> resume those discussions?
> 
> > I'd prefer Paolo to review
> > and merge broadcast SMI stuff as appropriate.  Paolo, makes sense?
> 
> If it helps, I can split the series into two "waves", and deal only with
> fw_cfg first.
2 waves looks better as vmgeneration stuff would depend on fw_cfg patches
so it would be good to first. And SMI could be follow up.

> 
> Thanks!
> Laszlo
> 
> > 
> > 
> >> Laszlo Ersek (6):
> >>   fw-cfg: turn FW_CFG_FILE_SLOTS into a device property
> >>   fw-cfg: expose "file_slots" parameter in fw_cfg_init_io_dma()
> >>   hw/i386/pc: introduce 2.9 machine types with 0x20 fw_cfg file slots
> >>   hw/isa/lpc_ich9: add SMI feature negotiation via fw_cfg
> >>   hw/isa/lpc_ich9: add broadcast SMI feature
> >>   hw/i386/pc_q35: advertise broadcast SMI if VCPU hotplug is turned off
> >>
> >> Michael S. Tsirkin (1):
> >>   fw-cfg: support writeable blobs
> >>
> >>  docs/specs/fw_cfg.txt          |  36 +++++++++---
> >>  hw/lm32/lm32_hwsetup.h         |   2 +-
> >>  include/hw/compat.h            |  11 ++++
> >>  include/hw/i386/ich9.h         |  15 ++++-
> >>  include/hw/i386/pc.h           |   4 ++
> >>  include/hw/loader.h            |   7 ++-
> >>  include/hw/nvram/fw_cfg.h      |   5 +-
> >>  include/hw/nvram/fw_cfg_keys.h |   7 ++-
> >>  hw/arm/virt-acpi-build.c       |   2 +-
> >>  hw/core/loader.c               |  18 +++---
> >>  hw/i386/acpi-build.c           |   4 +-
> >>  hw/i386/pc.c                   |   3 +-
> >>  hw/i386/pc_piix.c              |  16 +++++-
> >>  hw/i386/pc_q35.c               |  37 ++++++++++++-
> >>  hw/isa/lpc_ich9.c              |  92 +++++++++++++++++++++++++++++-
> >>  hw/nvram/fw_cfg.c              | 123 +++++++++++++++++++++++++++++++++++------
> >>  16 files changed, 326 insertions(+), 56 deletions(-)
> >>
> >> -- 
> >> 2.9.2
> 
>