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> > --- > 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;
