On Thu, 27 Aug 2020 09:40:34 -0400 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> From: Ani Sinha <a...@anisinha.ca> > > We introduce a new global flag 'acpi-root-pci-hotplug' for i440fx with which > we can turn on or off PCI device hotplug on the root bus. This flag can be > used to prevent all PCI devices from getting hotplugged or unplugged from the > root PCI bus. > This feature is targetted mostly towards Windows VMs. It is useful in cases > where some hypervisor admins want to deploy guest VMs in a way so that the > users of the guest OSes are not able to hot-eject certain PCI devices from > the Windows system tray. Laine has explained the use case here in detail: > https://www.redhat.com/archives/libvir-list/2020-February/msg00110.html > > Julia has resolved this issue for PCIE buses with the following commit: > 530a0963184e57e71a5b538 ("pcie_root_port: Add hotplug disabling option") > > This commit attempts to introduce similar behavior for PCI root buses used in > i440fx machine types (although in this case, we do not have a per-slot > capability to turn hotplug on or off). > > Usage: > -global PIIX4_PM.acpi-root-pci-hotplug=off > > By default, this option is enabled which means that hotplug is turned on for > the PCI root bus. > > The previously existing flag 'acpi-pci-hotplug-with-bridge-support' for > PCI-PCI > bridges remain as is and can be used along with this new flag to control PCI > hotplug on PCI bridges. > > This change has been tested using a Windows 2012R2 server guest image and also > with a Windows 2019 server guest image on a Ubuntu 18.04 host using the latest > master qemu from upstream. > > Signed-off-by: Ani Sinha <a...@anisinha.ca> > Message-Id: <20200821165403.26589-1-...@anisinha.ca> > Reviewed-by: Michael S. Tsirkin <m...@redhat.com> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > Tested-by: Igor Mammedov <imamm...@redhat.com> > Reviewed-by: Igor Mammedov <imamm...@redhat.com> A glitch in scripts? I didn't review nor tested this (v8) version > --- > include/hw/acpi/pcihp.h | 2 +- > hw/acpi/pcihp.c | 23 ++++++++++++++++++++++- > hw/acpi/piix4.c | 5 ++++- > 3 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h > index 8bc4a4c01d..02f4665767 100644 > --- a/include/hw/acpi/pcihp.h > +++ b/include/hw/acpi/pcihp.h > @@ -67,7 +67,7 @@ void acpi_pcihp_device_unplug_request_cb(HotplugHandler > *hotplug_dev, > Error **errp); > > /* Called on reset */ > -void acpi_pcihp_reset(AcpiPciHpState *s); > +void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off); > > extern const VMStateDescription vmstate_acpi_pcihp_pci_status; > > diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c > index 9e31ab2da4..39b1f74442 100644 > --- a/hw/acpi/pcihp.c > +++ b/hw/acpi/pcihp.c > @@ -104,6 +104,24 @@ static void acpi_set_pci_info(void) > } > } > > +static void acpi_pcihp_disable_root_bus(void) > +{ > + static bool root_hp_disabled; > + PCIBus *bus; > + > + if (root_hp_disabled) { > + return; > + } > + > + bus = find_i440fx(); > + if (bus) { > + /* setting the hotplug handler to NULL makes the bus > non-hotpluggable */ > + qbus_set_hotplug_handler(BUS(bus), NULL); > + } > + root_hp_disabled = true; > + return; > +} > + > static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque) > { > AcpiPciHpFind *find = opaque; > @@ -209,8 +227,11 @@ static void acpi_pcihp_update(AcpiPciHpState *s) > } > } > > -void acpi_pcihp_reset(AcpiPciHpState *s) > +void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off) > { > + if (acpihp_root_off) { > + acpi_pcihp_disable_root_bus(); > + } > acpi_set_pci_info(); > acpi_pcihp_update(s); > } > diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c > index 26bac4f16c..e6163bb6ce 100644 > --- a/hw/acpi/piix4.c > +++ b/hw/acpi/piix4.c > @@ -78,6 +78,7 @@ typedef struct PIIX4PMState { > > AcpiPciHpState acpi_pci_hotplug; > bool use_acpi_hotplug_bridge; > + bool use_acpi_root_pci_hotplug; > > uint8_t disable_s3; > uint8_t disable_s4; > @@ -324,7 +325,7 @@ static void piix4_pm_reset(DeviceState *dev) > pci_conf[0x5B] = 0x02; > } > pm_io_space_update(s); > - acpi_pcihp_reset(&s->acpi_pci_hotplug); > + acpi_pcihp_reset(&s->acpi_pci_hotplug, !s->use_acpi_root_pci_hotplug); > } > > static void piix4_pm_powerdown_req(Notifier *n, void *opaque) > @@ -635,6 +636,8 @@ static Property piix4_pm_properties[] = { > DEFINE_PROP_UINT8(ACPI_PM_PROP_S4_VAL, PIIX4PMState, s4_val, 2), > DEFINE_PROP_BOOL("acpi-pci-hotplug-with-bridge-support", PIIX4PMState, > use_acpi_hotplug_bridge, true), > + DEFINE_PROP_BOOL("acpi-root-pci-hotplug", PIIX4PMState, > + use_acpi_root_pci_hotplug, true), > DEFINE_PROP_BOOL("memory-hotplug-support", PIIX4PMState, > acpi_memory_hotplug.is_enabled, true), > DEFINE_PROP_END_OF_LIST(),
