On Mon, Sep 14, 2020 at 6:07 PM Igor Mammedov <imamm...@redhat.com> wrote:
>
> On Fri, 11 Sep 2020 23:37:51 +0530
> 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
> >
> > As a result of the patch, the following are the changes to the DSDT ACPI
> > table:
> >
> > @@ -858,38 +858,33 @@
> > Return (Zero)
> > }
> >
> > Method (_S2D, 0, NotSerialized) // _S2D: S2 Device State
> > {
> > Return (Zero)
> > }
> >
> > Method (_S3D, 0, NotSerialized) // _S3D: S3 Device State
> > {
> > Return (Zero)
> > }
> > }
> >
> > Device (S18)
> > {
> > - Name (_SUN, 0x03) // _SUN: Slot User Number
> > Name (_ADR, 0x00030000) // _ADR: Address
> > - Method (_EJ0, 1, NotSerialized) // _EJx: Eject Device
> > - {
> > - PCEJ (BSEL, _SUN)
> > - }
> > }
> >
> > Device (S20)
> > {
> > Name (_SUN, 0x04) // _SUN: Slot User Number
> > Name (_ADR, 0x00040000) // _ADR: Address
> > Method (_EJ0, 1, NotSerialized) // _EJx: Eject Device
> > {
> > PCEJ (BSEL, _SUN)
> > }
> > }
> >
> > Device (S28)
> > {
> > Name (_SUN, 0x05) // _SUN: Slot User Number
> > Name (_ADR, 0x00050000) // _ADR: Address
> > @@ -1148,37 +1143,32 @@
> > PCEJ (BSEL, _SUN)
> > }
> > }
> >
> > Device (SF8)
> > {
> > Name (_SUN, 0x1F) // _SUN: Slot User Number
> > Name (_ADR, 0x001F0000) // _ADR: Address
> > Method (_EJ0, 1, NotSerialized) // _EJx: Eject Device
> > {
> > PCEJ (BSEL, _SUN)
> > }
> > }
> >
> > Method (DVNT, 2, NotSerialized)
> > {
> > - If ((Arg0 & 0x08))
> > - {
> > - Notify (S18, Arg1)
> > - }
> > -
> > If ((Arg0 & 0x10))
> > {
> > Notify (S20, Arg1)
> > }
> >
> > If ((Arg0 & 0x20))
> > {
> > Notify (S28, Arg1)
> > }
> >
> > If ((Arg0 & 0x40))
> > {
> > Notify (S30, Arg1)
> > }
> >
> > If ((Arg0 & 0x80))
> >
> > 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: Igor Mammedov <imamm...@redhat.com>
Reviewed-by: Julia Suvorova <jus...@redhat.com>
>From the previous thread.
>
> > ---
> > hw/i386/acpi-build.c | 12 ++++++------
> > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index 7a5a8b3521..e079b686f5 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;
>
