hw/i386/acpi-build.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-)
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>
---
v2:
* squash 1/2 "acpi: x86: pcihp: cleanup devfn usage in build_append_pci_bus_devices()"
into the main patch
* drop Sxx -> Sxxx change as devfn fits into 2 digits anyway
* cleanup PCI_FUN/DEVFN and use func/devfn local variables instead
* fix typos
---
hw/i386/acpi-build.c | 44 ++++++++++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 14 deletions(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 17836149fe..a33ac8b91e 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -374,7 +374,7 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
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 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
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 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
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 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
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 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
/* 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));
}
}
--
2.27.0
Hi Igor, On Fri, Jul 23, 2021 at 12:04 PM Igor Mammedov <imammedo@redhat.com> wrote: > 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> > --- > v2: > * squash 1/2 "acpi: x86: pcihp: cleanup devfn usage in > build_append_pci_bus_devices()" > into the main patch > * drop Sxx -> Sxxx change as devfn fits into 2 digits anyway > * cleanup PCI_FUN/DEVFN and use func/devfn local variables instead > * fix typos > --- > hw/i386/acpi-build.c | 44 ++++++++++++++++++++++++++++++-------------- > 1 file changed, 30 insertions(+), 14 deletions(-) > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c > index 17836149fe..a33ac8b91e 100644 > --- a/hw/i386/acpi-build.c > +++ b/hw/i386/acpi-build.c > @@ -374,7 +374,7 @@ static void build_append_pci_bus_devices(Aml > *parent_scope, PCIBus *bus, > 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 @@ static void build_append_pci_bus_devices(Aml > *parent_scope, PCIBus *bus, > 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 @@ static void build_append_pci_bus_devices(Aml > *parent_scope, PCIBus *bus, > 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 @@ static void build_append_pci_bus_devices(Aml > *parent_scope, PCIBus *bus, > > 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 @@ static void build_append_pci_bus_devices(Aml > *parent_scope, PCIBus *bus, > /* 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)); > } > } > > -- > 2.27.0 > > Thanks for fixing it! Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com> Thanks, Marcel
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