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[PULL 09/13] acpi: pc: revert back to v5.2 PCI slot enumeration
From: |
Michael S. Tsirkin |
Subject: |
[PULL 09/13] acpi: pc: revert back to v5.2 PCI slot enumeration |
Date: |
Wed, 7 Jul 2021 11:03:24 -0400 |
From: Igor Mammedov <imammedo@redhat.com>
Commit [1] moved _SUN variable from only hot-pluggable to
all devices. This made linux kernel enumerate extra slots
that weren't present before. If extra slot happens to be
be enumerated first and there is a device in th same slot
but on other bridge, linux kernel will add -N suffix to
slot name of the later, thus changing NIC name compared to
QEMU 5.2. This in some case confuses systemd, if it is
using SLOT NIC naming scheme and interface name becomes
not the same as it was under QEMU-5.2.
Reproducer QEMU CLI:
-M pc-i440fx-5.2 -nodefaults \
-device pci-bridge,chassis_nr=1,id=pci.1,bus=pci.0,addr=0x3 \
-device virtio-net-pci,id=nic1,bus=pci.1,addr=0x1 \
-device virtio-net-pci,id=nic2,bus=pci.1,addr=0x2 \
-device virtio-net-pci,id=nic3,bus=pci.1,addr=0x3
with RHEL8 guest produces following results:
v5.2:
kernel: virtio_net virtio0 ens1: renamed from eth0
kernel: virtio_net virtio2 ens3: renamed from eth2
kernel: virtio_net virtio1 enp1s2: renamed from eth1
(slot 2 is assigned to empty bus 0 slot and virtio1
is assigned to 2-2 slot, and renaming falls back,
for some reason, to path based naming scheme)
v6.0:
kernel: virtio_net virtio0 ens1: renamed from eth0
kernel: virtio_net virtio2 ens3: renamed from eth2
systemd-udevd[299]: Error changing net interface name 'eth1' to 'ens3':
File exists
systemd-udevd[299]: could not rename interface '3' from 'eth1' to 'ens3':
File exists
(with commit [1] kernel assigns virtio2 to 3-2 slot
since bridge advertises _SUN=0x3 and kernel assigns
slot 3 to bridge. Still it manages to rename virtio2
correctly to ens3, however systemd gets confused with virtio1
where slot allocation exactly the same (2-2) as in 5.2 case
and tries to rename it to ens3 which is rightfully taken by
virtio2)
I'm not sure what breaks in systemd interface renaming (it probably
should be investigated), but on QEMU side we can safely revert
_SUN to 5.2 behavior (i.e. avoid cold-plugged bridges and non
hot-pluggable device classes), without breaking acpi-index, which uses
slot numbers but it doesn't have to use _SUN, it could use an arbitrary
variable name that has the same slot value).
It will help existing VMs to keep networking with non trivial
configs in working order since systemd will do its interface
renaming magic as it used to do.
1)
Fixes: b7f23f62e40 (pci: acpi: add _DSM method to PCI devices)
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20210624204229.998824-3-imammedo@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: John Sucaet <john.sucaet@ekinops.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/i386/acpi-build.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 796ffc6f5c..357437ff1d 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -435,11 +435,15 @@ static void build_append_pci_bus_devices(Aml
*parent_scope, PCIBus *bus,
aml_append(dev, aml_name_decl("_ADR", aml_int(slot << 16)));
if (bsel) {
- aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
+ /*
+ * Can't declare _SUN here for every device as it changes 'slot'
+ * enumeration order in linux kernel, so use another variable for
it
+ */
+ aml_append(dev, aml_name_decl("ASUN", aml_int(slot)));
method = aml_method("_DSM", 4, AML_SERIALIZED);
aml_append(method, aml_return(
aml_call6("PDSM", aml_arg(0), aml_arg(1), aml_arg(2),
- aml_arg(3), aml_name("BSEL"), aml_name("_SUN"))
+ aml_arg(3), aml_name("BSEL"), aml_name("ASUN"))
));
aml_append(dev, method);
}
@@ -466,6 +470,7 @@ static void build_append_pci_bus_devices(Aml *parent_scope,
PCIBus *bus,
aml_append(method, aml_return(aml_int(s3d)));
aml_append(dev, method);
} else if (hotplug_enabled_dev) {
+ aml_append(dev, aml_name_decl("_SUN", aml_int(slot)));
/* add _EJ0 to make slot hotpluggable */
method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
aml_append(method,
--
MST
- [PULL 00/13] pc,pci,virtio: bugfixes, improvements, Michael S. Tsirkin, 2021/07/07
- [PULL 01/13] virtio: disable ioeventfd for record/replay, Michael S. Tsirkin, 2021/07/07
- [PULL 03/13] hw/pci-host/q35: Ignore write of reserved PCIEXBAR LENGTH field, Michael S. Tsirkin, 2021/07/07
- [PULL 05/13] virtio-pci: Added check for virtio device in PCI config cbs., Michael S. Tsirkin, 2021/07/07
- [PULL 04/13] virtio-pci: Added check for virtio device presence in mm callbacks., Michael S. Tsirkin, 2021/07/07
- [PULL 02/13] virtio: Clarify MR transaction optimization, Michael S. Tsirkin, 2021/07/07
- [PULL 06/13] virtio-pci: Changed return values for "notify", "device" and "isr" read., Michael S. Tsirkin, 2021/07/07
- [PULL 07/13] migration: failover: reset partially_hotplugged, Michael S. Tsirkin, 2021/07/07
- [PULL 08/13] tests: acpi: prepare for changing DSDT tables, Michael S. Tsirkin, 2021/07/07
- [PULL 09/13] acpi: pc: revert back to v5.2 PCI slot enumeration,
Michael S. Tsirkin <=
- [PULL 10/13] tests: acpi: pc: update expected DSDT blobs, Michael S. Tsirkin, 2021/07/07
- [PULL 11/13] acpi/ged: fix reset cause, Michael S. Tsirkin, 2021/07/07
- [PULL 12/13] docs: add slot when adding new PCIe root port, Michael S. Tsirkin, 2021/07/07
- [PULL 13/13] MAINTAINERS: Add maintainer for vhost-user RNG implementation, Michael S. Tsirkin, 2021/07/07
- Re: [PULL 00/13] pc,pci,virtio: bugfixes, improvements, Peter Maydell, 2021/07/09