Re: [PATCH V2] Add a new PIIX option to control PCI hot unplugging of devices on non-root buses

[Ani Sinha <ani.sinha@nutanix.com>]

+julie
+ laine

Rebased patch to latest Qemu master. Only minimal changes.


> On Apr 28, 2020, at 3:46 PM, Ani Sinha <ani.sinha@nutanix.com> wrote:
> 
> A new option "use_acpi_unplug" is introduced for PIIX which will
> selectively only disable hot unplugging of both hot plugged and
> cold plugged PCI devices on non-root PCI buses. This will prevent
> hot unplugging of devices from Windows based guests from system
> tray but will not prevent devices from being hot plugged into the
> guest.
> 
> It has been tested on Windows guests.
> 
> Signed-off-by: Ani Sinha <ani.sinha@nutanix.com>
> ---
> hw/acpi/piix4.c      |  3 +++
> hw/i386/acpi-build.c | 40 ++++++++++++++++++++++++++--------------
> 2 files changed, 29 insertions(+), 14 deletions(-)
> 
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index 964d6f5..59fa707 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_pci_hotplug;
> +    bool use_acpi_unplug;
> 
>     uint8_t disable_s3;
>     uint8_t disable_s4;
> @@ -633,6 +634,8 @@ 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_pci_hotplug, true),
> +    DEFINE_PROP_BOOL("acpi-pci-hotunplug-enable-bridge", PIIX4PMState,
> +                     use_acpi_unplug, 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 23c77ee..71b3ac3 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -96,6 +96,7 @@ typedef struct AcpiPmInfo {
>     bool s3_disabled;
>     bool s4_disabled;
>     bool pcihp_bridge_en;
> +    bool pcihup_bridge_en;
>     uint8_t s4_val;
>     AcpiFadtData fadt;
>     uint16_t cpu_hp_io_base;
> @@ -240,6 +241,9 @@ 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->pcihup_bridge_en =
> +        object_property_get_bool(obj, "acpi-pci-hotunplug-enable-bridge",
> +                                 NULL);
> }
> 
> static void acpi_get_misc_info(AcpiMiscInfo *info)
> @@ -451,7 +455,8 @@ 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 pcihup_bridge_en)
> {
>     Aml *dev, *notify_method = NULL, *method;
>     QObject *bsel;
> @@ -479,11 +484,14 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
>                 dev = aml_device("S%.02X", PCI_DEVFN(slot, 0));
>                 aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
>                 aml_append(dev, aml_name_decl("_ADR", aml_int(slot << 16)));
> -                method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
> -                aml_append(method,
> -                    aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
> -                );
> -                aml_append(dev, method);
> +                if (pcihup_bridge_en || pci_bus_is_root(bus)) {
> +                    method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
> +                    aml_append(method,
> +                               aml_call2("PCEJ", aml_name("BSEL"),
> +                                         aml_name("_SUN"))
> +                        );
> +                    aml_append(dev, method);
> +                }
>                 aml_append(parent_scope, dev);
> 
>                 build_append_pcihp_notify_entry(notify_method, slot);
> @@ -537,12 +545,14 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
>             /* add _SUN/_EJ0 to make slot hotpluggable  */
>             aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
> 
> -            method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
> -            aml_append(method,
> -                aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
> -            );
> -            aml_append(dev, method);
> -
> +            if (pcihup_bridge_en || pci_bus_is_root(bus)) {
> +                method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
> +                aml_append(method,
> +                           aml_call2("PCEJ", aml_name("BSEL"),
> +                                     aml_name("_SUN"))
> +                    );
> +                aml_append(dev, method);
> +            }
>             if (bsel) {
>                 build_append_pcihp_notify_entry(notify_method, slot);
>             }
> @@ -553,7 +563,8 @@ 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,
> +                                         pcihup_bridge_en);
>         }
>         /* slot descriptor has been composed, add it into parent context */
>         aml_append(parent_scope, dev);
> @@ -2196,7 +2207,8 @@ 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->pcihup_bridge_en);
> 
>             if (TPM_IS_TIS_ISA(tpm)) {
>                 if (misc->tpm_version == TPM_VERSION_2_0) {
> -- 
> 1.9.4
>