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Tsirkin" , qemu-devel@nongnu.org, Aleksandar Markovic , Paolo Bonzini , Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= , Aurelien Jarno , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 21 Aug 2020 16:43:37 +0530 Ani Sinha wrote: > On Fri, Aug 21, 2020 at 2:46 PM Igor Mammedov wrote= : > > > > On Thu, 20 Aug 2020 22:11:41 +0530 > > Ani Sinha wrote: > > =20 > > > > On Aug 20, 2020, at 9:11 PM, Ani Sinha wrote: > > > > > > > > =EF=BB=BFOn Thu, Aug 20, 2020 at 7:37 PM Igor Mammedov wrote: =20 > > > >> =20 > > > >>> On Thu, 20 Aug 2020 14:51:56 +0530 > > > >>> Ani Sinha 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 fl= ag can be > > > >>> used to prevent all PCI devices from getting hotplugged or unplug= ged from the > > > >>> root PCI bus. > > > >>> This feature is targetted mostly towards Windows VMs. It is usefu= l 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 dev= ices from > > > >>> the Windows system tray. Laine has explained the use case here in= detail: > > > >>> https://www.redhat.com/archives/libvir-list/2020-February/msg0011= 0.html > > > >>> > > > >>> Julia has resolved this issue for PCIE buses with the following c= ommit: > > > >>> 530a0963184e57e71a5b538 ("pcie_root_port: Add hotplug disabling o= ption") > > > >>> > > > >>> This commit attempts to introduce similar behavior for PCI root b= uses 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=3Doff > > > >>> > > > >>> By default, this option is enabled which means that hotplug is tu= rned on for > > > >>> the PCI root bus. > > > >>> > > > >>> The previously existing flag 'acpi-pci-hotplug-with-bridge-suppor= t' 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 i= mage and also > > > >>> with a Windows 2019 server guest image on a Ubuntu 18.04 host usi= ng the latest > > > >>> master qemu from upstream (v5.1.0 tag). > > > >>> > > > >>> Signed-off-by: Ani Sinha > > > >>> --- > > > >>> 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; =20 > > > >> =20 > > > >>> @@ -595,8 +596,9 @@ static void piix4_acpi_system_hot_add_init(Me= moryRegion *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_hotpl= ug) > > > >>> + acpi_pcihp_init(OBJECT(s), &s->acpi_pci_hotplug, bus, pa= rent, > > > >>> + s->use_acpi_hotplug_bridge); =20 > > > >> 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 acc= ess no longer > > > >> described/present io ports. > > > >> > > > >> Without this hunk patch is fine, as a means to hide hotplug from W= indows. > > > >> > > > >> If you'd like to disable hw part, you will need to consider case w= here hotplug is > > > >> disabled completly and block all related AML and block device_add|= del. > > > >> So it would be a bit more than above hunk. =20 > > > > > > > > Ok maybe I will just remove it. > > > > =20 > > > >> > > > >> =20 > > > >>> s->cpu_hotplug_legacy =3D true; > > > >>> object_property_add_bool(OBJECT(s), "cpu-hotplug-legacy", > > > >>> @@ -635,6 +637,8 @@ static Property piix4_pm_properties[] =3D { > > > >>> DEFINE_PROP_UINT8(ACPI_PM_PROP_S4_VAL, PIIX4PMState, s4_val, = 2), > > > >>> DEFINE_PROP_BOOL("acpi-pci-hotplug-with-bridge-support", PIIX= 4PMState, > > > >>> 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 *ma= chine, AcpiPmInfo *pm) > > > >>> pm->pcihp_bridge_en =3D > > > >>> object_property_get_bool(obj, "acpi-pci-hotplug-with-brid= ge-support", > > > >>> NULL); > > > >>> + pm->pcihp_root_en =3D > > > >>> + object_property_get_bool(obj, "acpi-root-pci-hotplug", N= ULL); > > > >>> + > > > >>> } > > > >>> > > > >>> 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, PCIBu= s *bus, > > > >>> - bool pcihp_bridge_en) > > > >>> + bool pcihp_bridge_en, > > > >>> + bool pcihp_root_en) > > > >>> { > > > >>> Aml *dev, *notify_method =3D NULL, *method; > > > >>> QObject *bsel; > > > >>> PCIBus *sec; > > > >>> int i; > > > >>> + bool root_bus =3D pci_bus_is_root(bus); > > > >>> + bool root_pcihp_disabled =3D (root_bus && !pcihp_root_en); > > > >>> > > > >>> bsel =3D object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_= PROP_BSEL, NULL); > > > >>> - if (bsel) { > > > >>> + if (bsel && !root_pcihp_disabled) { =20 > > > >> > > > >> 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. =20 > > > > > > > > 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, Er= ror **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 i= t > > > > wouldn't work :( =20 > > > > > > By that I mean the devices attached to bridges also seems to be disab= led 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 buse= s. > > > > > > Any ideas? =20 > > Looking at acpi_set_pci_info() and debugging it might help. =20 >=20 > All my efforts in this space have failed to work :( I am feeling a > little frustrated and out of ideas. I am inclined to resend V2 with > the suggestions you suggested for the final patch unless you have > better ideas. That's why I've suggest to fix up this patch first, and work on hw part sep= arately. As for ideas, unfortunatly other than debugging it to see where it breaks, I don't have any other suggestions. (though that would require a bit more code studying about how ACPI PCI hotplug works. If You have concrete questions about the code, I might be able to clarify it for you.) > > =20 > > > =20 > > > > =20 > > > >> > > > >> =20 > > > >>> uint64_t bsel_val =3D qnum_get_uint(qobject_to(QNum, bsel= )); > > > >>> > > > >>> aml_append(parent_scope, aml_name_decl("BSEL", aml_int(bs= el_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 devi= ces */ > > > >>> dev =3D aml_device("S%.02X", PCI_DEVFN(slot, 0)); > > > >>> aml_append(dev, aml_name_decl("_SUN", aml_int(slo= t))); > > > >>> @@ -419,7 +429,7 @@ static void build_append_pci_bus_devices(Aml = *parent_scope, PCIBus *bus, > > > >>> method =3D 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(Am= l *parent_scope, PCIBus *bus, > > > >>> */ > > > >>> PCIBus *sec_bus =3D pci_bridge_get_sec_bus(PCI_BRIDGE= (pdev)); > > > >>> > > > >>> - build_append_pci_bus_devices(dev, sec_bus, pcihp_bri= dge_en); > > > >>> + build_append_pci_bus_devices(dev, sec_bus, pcihp_bri= dge_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 =3D aml_method("PCNT", 0, AML_NOTSERIALIZED); > > > >>> > > > >>> /* If bus supports hotplug select it and notify about local e= vents */ > > > >>> - if (bsel) { > > > >>> + if (bsel && !root_pcihp_disabled) { > > > >>> uint64_t bsel_val =3D 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 =3D aml_scope("PCI0"); > > > >>> /* Scan all PCI buses. Generate tables to support hot= plug. */ > > > >>> - build_append_pci_bus_devices(scope, bus, pm->pcihp_b= ridge_en); > > > >>> + build_append_pci_bus_devices(scope, bus, pm->pcihp_b= ridge_en, > > > >>> + pm->pcihp_root_en); > > > >>> > > > >>> if (TPM_IS_TIS_ISA(tpm)) { > > > >>> if (misc->tpm_version =3D=3D TPM_VERSION_2_0) { = =20 > > > >> =20 > > > =20 > > =20 >=20