On Thu, 20 Aug 2020 22:11:41 +0530 Ani Sinha <a...@anisinha.ca> wrote:
> > On Aug 20, 2020, at 9:11 PM, Ani Sinha <a...@anisinha.ca> wrote: > > > > On Thu, Aug 20, 2020 at 7:37 PM Igor Mammedov <imamm...@redhat.com> wrote: > > > >> > >>> On Thu, 20 Aug 2020 14:51:56 +0530 > >>> Ani Sinha <a...@anisinha.ca> wrote: > >>> > >>> 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 (v5.1.0 tag). > >>> > >>> Signed-off-by: Ani Sinha <a...@anisinha.ca> > >>> --- > >>> hw/acpi/piix4.c | 8 ++++++-- > >>> hw/i386/acpi-build.c | 26 +++++++++++++++++++------- > >>> 2 files changed, 25 insertions(+), 9 deletions(-) > >>> > >>> Change Log: > >>> V5..V6: specified upstream master tag information off which this patch is > >>> based off of. > >>> > >>> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c > >>> index 26bac4f16c..4f436e5bf3 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; > >> > >>> @@ -595,8 +596,9 @@ static void > >>> piix4_acpi_system_hot_add_init(MemoryRegion *parent, > >>> "acpi-gpe0", GPE_LEN); > >>> memory_region_add_subregion(parent, GPE_BASE, &s->io_gpe); > >>> > >>> - acpi_pcihp_init(OBJECT(s), &s->acpi_pci_hotplug, bus, parent, > >>> - s->use_acpi_hotplug_bridge); > >>> + if (s->use_acpi_hotplug_bridge || s->use_acpi_root_pci_hotplug) > >>> + acpi_pcihp_init(OBJECT(s), &s->acpi_pci_hotplug, bus, parent, > >>> + s->use_acpi_hotplug_bridge); > >> If intent was to disable hardware part of ACPI hotplug, > >> then this hunk is not enough. I'd say it introduces bug since you are > >> leaving > >> device_add/del route open and "_E01" AML code around trying to access no > >> longer > >> described/present io ports. > >> > >> Without this hunk patch is fine, as a means to hide hotplug from Windows. > >> > >> If you'd like to disable hw part, you will need to consider case where > >> hotplug is > >> disabled completly and block all related AML and block device_add|del. > >> So it would be a bit more than above hunk. > > > > Ok maybe I will just remove it. > > > >> > >> > >>> s->cpu_hotplug_legacy = true; > >>> object_property_add_bool(OBJECT(s), "cpu-hotplug-legacy", > >>> @@ -635,6 +637,8 @@ 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(), > >>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c > >>> index b7bcbbbb2a..19a1702ad1 100644 > >>> --- a/hw/i386/acpi-build.c > >>> +++ b/hw/i386/acpi-build.c > >>> @@ -95,6 +95,7 @@ typedef struct AcpiPmInfo { > >>> bool s3_disabled; > >>> bool s4_disabled; > >>> bool pcihp_bridge_en; > >>> + bool pcihp_root_en; > >>> uint8_t s4_val; > >>> AcpiFadtData fadt; > >>> uint16_t cpu_hp_io_base; > >>> @@ -245,6 +246,9 @@ static void acpi_get_pm_info(MachineState *machine, > >>> AcpiPmInfo *pm) > >>> pm->pcihp_bridge_en = > >>> object_property_get_bool(obj, > >>> "acpi-pci-hotplug-with-bridge-support", > >>> NULL); > >>> + pm->pcihp_root_en = > >>> + object_property_get_bool(obj, "acpi-root-pci-hotplug", NULL); > >>> + > >>> } > >>> > >>> static void acpi_get_misc_info(AcpiMiscInfo *info) > >>> @@ -337,15 +341,18 @@ static void build_append_pcihp_notify_entry(Aml > >>> *method, int slot) > >>> } > >>> > >>> static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus, > >>> - bool pcihp_bridge_en) > >>> + bool pcihp_bridge_en, > >>> + bool pcihp_root_en) > >>> { > >>> Aml *dev, *notify_method = NULL, *method; > >>> QObject *bsel; > >>> PCIBus *sec; > >>> int i; > >>> + bool root_bus = pci_bus_is_root(bus); > >>> + bool root_pcihp_disabled = (root_bus && !pcihp_root_en); > >>> > >>> bsel = object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_PROP_BSEL, > >>> NULL); > >>> - if (bsel) { > >>> + if (bsel && !root_pcihp_disabled) { > >> > >> have you considered to make bus not hotpluggable, > >> which should make it not to have bsel, and hence skip this branch without > >> root_pcihp_disabled? > >> > >> see: acpi_set_bsel() > >> > >> > >> maybe you can drop pcihp_root_en and use bsel instead of it then. > >> > >> it also should block device_add/del route. > > > > This is a good idea. Therefore, I tried this: > > > > --- a/hw/acpi/piix4.c > > +++ b/hw/acpi/piix4.c > > @@ -28,6 +28,7 @@ > > #include "hw/pci/pci.h" > > #include "hw/qdev-properties.h" > > #include "hw/acpi/acpi.h" > > +#include "hw/pci/pci_bus.h" > > #include "sysemu/runstate.h" > > #include "sysemu/sysemu.h" > > #include "sysemu/xen.h" > > @@ -507,7 +508,9 @@ static void piix4_pm_realize(PCIDevice *dev, Error > > **errp) > > > > piix4_acpi_system_hot_add_init(pci_address_space_io(dev), > > pci_get_bus(dev), s); > > - qbus_set_hotplug_handler(BUS(pci_get_bus(dev)), OBJECT(s)); > > + if (s->use_acpi_root_pci_hotplug || > > + !pci_bus_is_root(pci_get_bus(dev))) > > + qbus_set_hotplug_handler(BUS(pci_get_bus(dev)), OBJECT(s)); > > > > piix4_pm_add_propeties(s); > > } > > > > > > but this does not seem to be working. I am out of ideas as to why it > > wouldn't work :( > > By that I mean the devices attached to bridges also seems to be disabled from > hotplug from within Windows. I do not understand why that would be the case > when the pci_bus_is_root() should be false for the secondary buses. > > Any ideas? Looking at acpi_set_pci_info() and debugging it might help. > > > > >> > >> > >>> uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel)); > >>> > >>> aml_append(parent_scope, aml_name_decl("BSEL", > >>> aml_int(bsel_val))); > >>> @@ -361,6 +368,9 @@ static void build_append_pci_bus_devices(Aml > >>> *parent_scope, PCIBus *bus, > >>> bool bridge_in_acpi; > >>> > >>> if (!pdev) { > >>> + /* skip if pci hotplug for the root bus is disabled */ > >>> + if (root_pcihp_disabled) > >>> + continue; > >>> if (bsel) { /* add hotplug slots for non present devices */ > >>> dev = aml_device("S%.02X", PCI_DEVFN(slot, 0)); > >>> aml_append(dev, aml_name_decl("_SUN", aml_int(slot))); > >>> @@ -419,7 +429,7 @@ static void build_append_pci_bus_devices(Aml > >>> *parent_scope, PCIBus *bus, > >>> method = aml_method("_S3D", 0, AML_NOTSERIALIZED); > >>> aml_append(method, aml_return(aml_int(s3d))); > >>> aml_append(dev, method); > >>> - } else if (hotplug_enabled_dev) { > >>> + } else if (hotplug_enabled_dev && !root_pcihp_disabled) { > >>> /* add _SUN/_EJ0 to make slot hotpluggable */ > >>> aml_append(dev, aml_name_decl("_SUN", aml_int(slot))); > >>> > >>> @@ -439,13 +449,14 @@ static void build_append_pci_bus_devices(Aml > >>> *parent_scope, PCIBus *bus, > >>> */ > >>> PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev)); > >>> > >>> - build_append_pci_bus_devices(dev, sec_bus, pcihp_bridge_en); > >>> + build_append_pci_bus_devices(dev, sec_bus, pcihp_bridge_en, > >>> + pcihp_root_en); > >>> } > >>> /* slot descriptor has been composed, add it into parent context > >>> */ > >>> aml_append(parent_scope, dev); > >>> } > >>> > >>> - if (bsel) { > >>> + if (bsel && !root_pcihp_disabled) { > >>> aml_append(parent_scope, notify_method); > >>> } > >>> > >>> @@ -455,7 +466,7 @@ static void build_append_pci_bus_devices(Aml > >>> *parent_scope, PCIBus *bus, > >>> method = aml_method("PCNT", 0, AML_NOTSERIALIZED); > >>> > >>> /* If bus supports hotplug select it and notify about local events */ > >>> - if (bsel) { > >>> + if (bsel && !root_pcihp_disabled) { > >>> uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel)); > >>> > >>> aml_append(method, aml_store(aml_int(bsel_val), > >>> aml_name("BNUM"))); > >>> @@ -1818,7 +1829,8 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, > >>> if (bus) { > >>> Aml *scope = aml_scope("PCI0"); > >>> /* Scan all PCI buses. Generate tables to support hotplug. */ > >>> - build_append_pci_bus_devices(scope, bus, > >>> pm->pcihp_bridge_en); > >>> + build_append_pci_bus_devices(scope, bus, pm->pcihp_bridge_en, > >>> + pm->pcihp_root_en); > >>> > >>> if (TPM_IS_TIS_ISA(tpm)) { > >>> if (misc->tpm_version == TPM_VERSION_2_0) { > >> >
