@@ -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;
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 <ani@anisinha.ca> --- 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.