Re: [PATCH 0/5] buses: switch to 3-phase-reset

[Michael S. Tsirkin]

On Fri, Jan 19, 2024 at 04:35:07PM +0000, Peter Maydell wrote:
> This patchset switches the handful of bus types that implement a
> reset method over to using the 3-phase-reset APIs, and then removes
> the transitional infrastructure from the core bus class that was
> supporting the ability to have bus types that use old-style reset.
> 
> I wrote this ages ago and recently picked it back up because of a
> recent PCI related reset ordering problem noted by Peter Xu.  I'm not
> sure if this patchset is necessary as a part of fixing that ordering
> problem (it might even be possible now to have the intel_iommu device
> use 3-phase reset and put the relevant parts of its reset into the
> 'exit' phase), but either way we really ought to do this cleanup
> to reduce the amount of legacy/transitional handling we have.
> 
> In theory this patchset should be fine and shouldn't be changing
> behaviour.  On the other hand the reason I never sent it out when I
> originally wrote it was that I ran into a test failure in the
> BootLinuxConsole.test_sh4_r2d avocado test.  Rerunning all the
> avocado tests I don't see that failing now, so maybe I was just
> confused by a flaky test back then.
> 
> In any case, this could probably use a thorough soak testing with
> workloads that do resets of the PCI bus; I've only done 'make check'
> and 'make check-avocado' on it.  But I wanted to get it out onto the
> list anyway.
> 
> thanks
> -- PMM

>From a quick look, we need this cleanup

Acked-by: Michael S. Tsirkin <mst@redhat.com>

I'll try some tests too, and report.

> Peter Maydell (5):
>   pci: Switch bus reset to 3-phase-reset
>   vmbus: Switch bus reset to 3-phase-reset
>   adb: Switch bus reset to 3-phase-reset
>   hw/s390x/css-bridge: switch virtual-css bus to 3-phase-reset
>   hw/core: Remove transitional infrastructure from BusClass
> 
>  include/hw/qdev-core.h |  2 --
>  hw/core/bus.c          | 67 ------------------------------------------
>  hw/hyperv/vmbus.c      |  7 +++--
>  hw/input/adb.c         |  7 +++--
>  hw/pci/pci.c           | 10 ++++---
>  hw/s390x/css-bridge.c  |  5 ++--
>  6 files changed, 17 insertions(+), 81 deletions(-)
> 
> -- 
> 2.34.1