On Fri, Sep 4, 2020 at 9:18 PM Julia Suvorova <[email protected]> wrote: > > On Fri, Sep 4, 2020 at 10:25 AM Ani Sinha <[email protected]> wrote: > > > > Cold plugged bridges should not be hot unpluggable, even when their hotplug > > property > > (acpi-pci-hotplug-with-bridge-support) is turned off. > > Unplugging a cold-plugged bridge is impossible already, see > acpi_pcihp_pc_no_hotplug().
Ah cool. So all the more reason we should fix this because guest OSes should not think that the device is hot-unpluggable. > > Best regards, Julia Suvorova. > > > 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. When > > devices are attached to the bridge, the bridge is ultimately not > > hot-unpluggable. 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- > > 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 running on Ubuntu > > host. This > > change is based off of upstream qemu master branch tag v5.1.0. > > > > Signed-off-by: Ani Sinha <[email protected]> > > --- > > 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 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 > > >
