From 0e84fd3b98feb2bdbfea75b9f7ff7993b2d5300f Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Thu, 2 Mar 2023 17:15:18 +0100 Subject: [PATCH] x86: pcihp: fix missing bridge AML when intermediate root-port has 'hotplug=off' set (I practice [1] hasn't broke anything since on hardware side we unset hotplug_handler on such intermediate port => hotplug behind it has never worked) When deciding if bridge should be described, the original condition was cold_plugged_bridge && pcihp_bridge_en which was replaced [1] by bridge has ACPI_PCIHP_PROP_BSEL the later however is not the same thing as the original and flips to false if intermediate bridge has hotplug turned off (root-port with 'hotplug=off' option). Since we already in build_pci_bridge_aml(), the question if it's bridge is answered. Use DeviceState::hotplugged to make decision if bridge should describe its slots. What's left out is pcihp_bridge_en, which tells us if ACPI bridge hotplug is enabled. With hotplug and non hotplug part now being mostly separated, omitting this check will only lead to colplugged bridges describe occupied slots in case when ACPI bridge hotplug is disabled. Which makes behavior consistent with occupied slots on hostbridge. Ex (pc/DSDT.hpbrroot diff): ... Device (S20) { Name (_ADR, 0x00040000) // _ADR: Address + Device (S08) + { + Name (_ADR, 0x00010000) // _ADR: Address + } + + Device (S10) + { + Name (_ADR, 0x00020000) // _ADR: Address + } } ... PS: testing shows that above doesn't affect adversely guest OS behavior: i.e. if ACPI bridge hotplug is enabled it's expected behaviour, and with ACPI bridge hotplug is disabled (a.k. native hotplug), it doesn't break slot enumeration nor native hotplug. (tested with RHEL9.0 and WS2022). 1) Fixes: 6c36ec46b0d ("pcihp: make bridge describe itself using AcpiDevAmlIfClass:build_dev_aml") Signed-off-by: Igor Mammedov Message-Id: <20230302161543.286002-10-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/acpi/pci-bridge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/acpi/pci-bridge.c b/hw/acpi/pci-bridge.c index 5f3ee5157f..4fbf6da6ad 100644 --- a/hw/acpi/pci-bridge.c +++ b/hw/acpi/pci-bridge.c @@ -21,7 +21,7 @@ void build_pci_bridge_aml(AcpiDevAmlIf *adev, Aml *scope) { PCIBridge *br = PCI_BRIDGE(adev); - if (object_property_find(OBJECT(&br->sec_bus), ACPI_PCIHP_PROP_BSEL)) { + if (!DEVICE(br)->hotplugged) { build_append_pci_bus_devices(scope, pci_bridge_get_sec_bus(br)); } }