Julia Michael, Can you please provide your inputs on this one and the corresponding unit tests?
On Fri, Sep 4, 2020 at 9:40 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> > > --- > > 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 > > > >
