qemu/hw/acpi/pci-bridge.c

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/*
* QEMU ACPI PCI bridge
*
* Copyright (c) 2023 Red Hat, Inc.
*
* Author:
* Igor Mammedov <imammedo@redhat.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/acpi/pci.h"
#include "hw/pci/pci_bridge.h"
#include "hw/acpi/pcihp.h"
void build_pci_bridge_aml(AcpiDevAmlIf *adev, Aml *scope)
{
PCIBridge *br = PCI_BRIDGE(adev);
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 <imammedo@redhat.com> Message-Id: <20230302161543.286002-10-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-03-02 19:15:18 +03:00
if (!DEVICE(br)->hotplugged) {
PCIBus *sec_bus = pci_bridge_get_sec_bus(br);
build_append_pci_bus_devices(scope, sec_bus);
/*
* generate hotplug slots descriptors if
* bridge has ACPI PCI hotplug attached,
*/
if (object_property_find(OBJECT(sec_bus), ACPI_PCIHP_PROP_BSEL)) {
build_append_pcihp_slots(scope, sec_bus);
}
}
}