On Fri, Sep 11, 2020 at 9:45 PM Ani Sinha <a...@anisinha.ca> wrote:
>
> On Fri, Sep 11, 2020 at 9:39 PM Michael S. Tsirkin <m...@redhat.com> wrote:
> >
> > On Fri, Sep 11, 2020 at 09:35:42PM +0530, Ani Sinha wrote:
> > > On Fri, Sep 11, 2020 at 9:22 PM Michael S. Tsirkin <m...@redhat.com>
> > > wrote:
> > > >
> > > > On Thu, Sep 10, 2020 at 12:19:19AM +0530, Ani Sinha wrote:
> > > > > On Sep 10, 2020, 00:00 +0530, Ani Sinha <a...@anisinha.ca>, wrote:
> > > > >
> > > > > On Sep 9, 2020, 23:20 +0530, Julia Suvorova <jus...@redhat.com>,
> > > > > wrote:
> > > > >
> > > > > On Fri, Sep 4, 2020 at 6:10 PM Ani Sinha <a...@anisinha.ca>
> > > > > wrote:
> > > > >
> > > > >
> > > > >
> > > > > Cold plugged bridges are not hot unpluggable, even when
> > > > > their
> > > > > hotplug
> > > > >
> > > > > property (acpi-pci-hotplug-with-bridge-support) is turned
> > > > > off.
> > > > > Please see
> > > > >
> > > > > the function acpi_pcihp_pc_no_hotplug() (thanks Julia).
> > > > > However,
> > > > > with
> > > > >
> > > > > the current implementaton, windows would try to
> > > > > hot-unplug a pci
> > > > > bridge when
> > > > >
> > > > > it's hotplug switch is off. This is regardless of whether
> > > > > there are
> > > > > devices
> > > > >
> > > > > attached to the bridge. This is because we add amls like
> > > > > _EJ0 etc
> > > > > for the
> > > > >
> > > > > pci slot where the bridge is cold plugged. We have a demo
> > > > > video
> > > > > here:
> > > > >
> > > > > https://youtu.be/pME2sjyQweo
> > > > >
> > > > >
> > > > >
> > > > > In this fix, we identify a cold plugged bridge and for
> > > > > cold plugged
> > > > > bridges,
> > > > >
> > > > > we do not add the appropriate amls and acpi methods that
> > > > > are used
> > > > > by the OS
> > > > >
> > > > > to identify a hot-pluggable/unpluggable pci device. After
> > > > > this
> > > > > change, Windows
> > > > >
> > > > > does not show an option to eject the PCI bridge. A demo
> > > > > video is
> > > > > here:
> > > > >
> > > > > https://youtu.be/kbgej5B9Hgs
> > > > >
> > > > >
> > > > >
> > > > > While at it, I have also updated a stale comment.
> > > > >
> > > > >
> > > > >
> > > > > This change is tested with a Windows 2012R2 guest image
> > > > > and Windows
> > > > > 2019 server
> > > > >
> > > > > guest image running on Ubuntu 18.04 host. This change is
> > > > > based off
> > > > > of upstream
> > > > >
> > > > > qemu master branch tag v5.1.0.
> > > > >
> > > > >
> > > > >
> > > > > Signed-off-by: Ani Sinha <a...@anisinha.ca>
> > > > >
> > > > >
> > > > >
> > > > > Reviewed-by: Julia Suvorova <jus...@redhat.com>
> > > > >
> > > > >
> > > > >
> > > > > BTW, aren't all bridges handled in
> > > > > build_append_pci_bus_devices()
> > > > > cold-plugged?
> > > > >
> > > > >
> > > > >
> > > > > Yes they are.
> > > > >
> > > > >
> > > > > Maybe as an improvement we can simply identify a bridge instead of a
> > > > > cold
> > > > > plugged bridge. However let’s have that improvement as a separate
> > > > > patch on top
> > > > > of this. Also let’s see what Igor thinks.
> > > >
> > > > Well this changes acpi tables so I don't see how this will pass
> > > > the unit tests. Did you test this change?
> > >
> > > There were no unit tests to cover this bridge flag. I have added the
> > > unit tests. It's the same one you have queued.
> >
> >
> > Hmm. somehow the new tests fail for me ...
>
> Maybe you need to pull this change out, make sure the tests passes and
> then apply it again:
>
> commit b26b2241baefc51fe2069b83cea9cfa654e75a43 (HEAD -> v5.1.0)
> Author: Ani Sinha <a...@anisinha.ca>
> Date: Tue Sep 1 15:19:22 2020 +0530
>
> piix4: don't reserve hw resources when hotplug is off globally
>
> When acpi hotplug is turned off for both root pci bus as well as for pci
> bridges, we should not generate the related amls for DSDT table or
> initialize
> related hw ports or reserve hw resources. This change makes sure all those
> operations are turned off in the case acpi pci hotplug is off globally.
>
> Signed-off-by: Ani Sinha <a...@anisinha.ca>
For this patch, I have not sent any updated unit tests.
>
>
> >
> > > >
> > > >
> > > > >
> > > > >
> > > > >
> > > > > ---
> > > > >
> > > > > hw/i386/acpi-build.c | 12 ++++++------
> > > > >
> > > > > 1 file changed, 6 insertions(+), 6 deletions(-)
> > > > >
> > > > >
> > > > >
> > > > > changelog:
> > > > >
> > > > > v3: commit log updates providing more accurate
> > > > > information as
> > > > > received from Julia.
> > > > >
> > > > > v2: cosmetic commit log updates with patch testing
> > > > > information.
> > > > >
> > > > > v1: initial patch.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > > >
> > > > > index b7bcbbbb2a..90b863f4ec 100644
> > > > >
> > > > > --- a/hw/i386/acpi-build.c
> > > > >
> > > > > +++ b/hw/i386/acpi-build.c
> > > > >
> > > > > @@ -359,6 +359,7 @@ static void
> > > > > build_append_pci_bus_devices(Aml
> > > > > *parent_scope, PCIBus *bus,
> > > > >
> > > > > int slot = PCI_SLOT(i);
> > > > >
> > > > > bool hotplug_enabled_dev;
> > > > >
> > > > > bool bridge_in_acpi;
> > > > >
> > > > > + bool cold_plugged_bridge;
> > > > >
> > > > >
> > > > >
> > > > > if (!pdev) {
> > > > >
> > > > > if (bsel) { /* add hotplug slots for non present devices
> > > > > */
> > > > >
> > > > > @@ -380,15 +381,14 @@ static void
> > > > > build_append_pci_bus_devices(Aml
> > > > > *parent_scope, PCIBus *bus,
> > > > >
> > > > > pc = PCI_DEVICE_GET_CLASS(pdev);
> > > > >
> > > > > dc = DEVICE_GET_CLASS(pdev);
> > > > >
> > > > >
> > > > >
> > > > > - /* When hotplug for bridges is enabled, bridges are
> > > > >
> > > > > - * described in ACPI separately (see build_pci_bus_end).
> > > > >
> > > > > - * In this case they aren't themselves hot-pluggable.
> > > > >
> > > > > + /*
> > > > >
> > > > > + * Cold plugged bridges aren't themselves hot-pluggable.
> > > > >
> > > > > * Hotplugged bridges *are* hot-pluggable.
> > > > >
> > > > > */
> > > > >
> > > > > - bridge_in_acpi = pc->is_bridge && pcihp_bridge_en &&
> > > > >
> > > > > - !DEVICE(pdev)->hotplugged;
> > > > >
> > > > > + cold_plugged_bridge = pc->is_bridge &&
> > > > > !DEVICE(pdev)->hotplugged;
> > > > >
> > > > > + bridge_in_acpi = cold_plugged_bridge && pcihp_bridge_en;
> > > > >
> > > > >
> > > > >
> > > > > - hotplug_enabled_dev = bsel && dc->hotpluggable && !
> > > > > bridge_in_acpi;
> > > > >
> > > > > + hotplug_enabled_dev = bsel && dc->hotpluggable && !
> > > > > cold_plugged_bridge;
> > > > >
> > > > >
> > > > >
> > > > > if (pc->class_id == PCI_CLASS_BRIDGE_ISA) {
> > > > >
> > > > > continue;
> > > > >
> > > > > --
> > > > >
> > > > > 2.17.1
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> >
