acpi: x86: pcihp: add support hotplug on multifunction bridges
Commit [1] switched PCI hotplug from native to ACPI one by default.
That however breaks hotplug on following CLI that used to work:
-nodefaults -machine q35 \
-device pcie-root-port,id=pcie-root-port-0,multifunction=on,bus=pcie.0,addr=0x1,chassis=1 \
-device pcie-root-port,id=pcie-root-port-1,port=0x1,addr=0x1.0x1,bus=pcie.0,chassis=2
where PCI device is hotplugged to pcie-root-port-1 with error on guest side:
ACPI BIOS Error (bug): Could not resolve symbol [^S0B.PCNT], AE_NOT_FOUND (20201113/psargs-330)
ACPI Error: Aborting method \_SB.PCI0.PCNT due to previous error (AE_NOT_FOUND) (20201113/psparse-531)
ACPI Error: Aborting method \_GPE._E01 due to previous error (AE_NOT_FOUND) (20201113/psparse-531)
ACPI Error: AE_NOT_FOUND, while evaluating GPE method [_E01] (20201113/evgpe-515)
cause is that QEMU's ACPI hotplug never supported functions other then 0
and due to bug it was generating notification entries for not described
functions.
Technically there is no reason not to describe cold-plugged bridges
(root ports) on functions other then 0, as they similarly to bridge
on function 0 are unpluggable.
So since we need to describe multifunction devices iterate over
fuctions as well. But describe only cold-plugged bridges[root ports]
on functions other than 0 as well.
1)
Fixes: 17858a169508609ca9063c544833e5a1adeb7b52 (hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35)
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reported-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20210723090424.2092226-1-imammedo@redhat.com>
Fixes: 17858a169508609ca9063c544833e5a1adeb7b52 (hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35)<br>
Signed-off-by: Igor Mammedov <<a href="mailto:imammedo@redhat.com" target="_blank">imammedo@redhat.com</a>><br>
Reported-by: Laurent Vivier <<a href="mailto:lvivier@redhat.com" target="_blank">lvivier@redhat.com</a>><br>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 1783614..a33ac8b 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -374,7 +374,7 @@
Aml *dev, *notify_method = NULL, *method;
QObject *bsel;
PCIBus *sec;
- int i;
+ int devfn;
bsel = object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_PROP_BSEL, NULL);
if (bsel) {
@@ -384,23 +384,31 @@
notify_method = aml_method("DVNT", 2, AML_NOTSERIALIZED);
}
- for (i = 0; i < ARRAY_SIZE(bus->devices); i += PCI_FUNC_MAX) {
+ for (devfn = 0; devfn < ARRAY_SIZE(bus->devices); devfn++) {
DeviceClass *dc;
PCIDeviceClass *pc;
- PCIDevice *pdev = bus->devices[i];
- int slot = PCI_SLOT(i);
+ PCIDevice *pdev = bus->devices[devfn];
+ int slot = PCI_SLOT(devfn);
+ int func = PCI_FUNC(devfn);
+ /* ACPI spec: 1.0b: Table 6-2 _ADR Object Bus Types, PCI type */
+ int adr = slot << 16 | func;
bool hotplug_enabled_dev;
bool bridge_in_acpi;
bool cold_plugged_bridge;
if (!pdev) {
- if (bsel) { /* add hotplug slots for non present devices */
+ /*
+ * add hotplug slots for non present devices.
+ * hotplug is supported only for non-multifunction device
+ * so generate device description only for function 0
+ */
+ if (bsel && !func) {
if (pci_bus_is_express(bus) && slot > 0) {
break;
}
- dev = aml_device("S%.02X", PCI_DEVFN(slot, 0));
+ dev = aml_device("S%.02X", devfn);
aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
- aml_append(dev, aml_name_decl("_ADR", aml_int(slot << 16)));
+ aml_append(dev, aml_name_decl("_ADR", aml_int(adr)));
method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
aml_append(method,
aml_call2("PCEJ", aml_name("BSEL"), aml_name("_SUN"))
@@ -436,9 +444,18 @@
continue;
}
- /* start to compose PCI slot descriptor */
- dev = aml_device("S%.02X", PCI_DEVFN(slot, 0));
- aml_append(dev, aml_name_decl("_ADR", aml_int(slot << 16)));
+ /*
+ * allow describing coldplugged bridges in ACPI even if they are not
+ * on function 0, as they are not unpluggable, for all other devices
+ * generate description only for function 0 per slot
+ */
+ if (func && !bridge_in_acpi) {
+ continue;
+ }
+
+ /* start to compose PCI device descriptor */
+ dev = aml_device("S%.02X", devfn);
+ aml_append(dev, aml_name_decl("_ADR", aml_int(adr)));
if (bsel) {
/*
@@ -496,7 +513,7 @@
build_append_pci_bus_devices(dev, sec_bus, pcihp_bridge_en);
}
- /* slot descriptor has been composed, add it into parent context */
+ /* device descriptor has been composed, add it into parent context */
aml_append(parent_scope, dev);
}
@@ -525,13 +542,12 @@
/* Notify about child bus events in any case */
if (pcihp_bridge_en) {
QLIST_FOREACH(sec, &bus->child, sibling) {
- int32_t devfn = sec->parent_dev->devfn;
-
if (pci_bus_is_root(sec)) {
continue;
}
- aml_append(method, aml_name("^S%.02X.PCNT", devfn));
+ aml_append(method, aml_name("^S%.02X.PCNT",
+ sec->parent_dev->devfn));
}
}
