From 456bb6cb658b9d332fa0b5b91946916b48ed449e Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Thu, 29 Jul 2021 07:42:10 -0400 Subject: [PATCH 09/39] acpi: pc: revert back to v5.2 PCI slot enumeration RH-Author: Miroslav Rezanina RH-MergeRequest: 32: Synchronize with RHEL-AV 8.5 release 27 to RHEL 9 RH-Commit: [1/15] 57222343ccae17b99b4e166798d4d0eecca2e22b (mrezanin/centos-src-qemu-kvm) RH-Bugzilla: 1957194 RH-Acked-by: Stefano Garzarella RH-Acked-by: Kevin Wolf RH-Acked-by: Igor Mammedov RH-Acked-by: Andrew Jones 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 Message-Id: <20210624204229.998824-3-imammedo@redhat.com> Reviewed-by: Stefan Hajnoczi Tested-by: John Sucaet Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 7193d7cdd93e50f0e5f09803b98d27d3f9b147ac) Signed-off-by: Igor Mammedov Signed-off-by: Miroslav Rezanina --- 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 de98750aef..dbee0cd3bc 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -432,11 +432,15 @@ 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); } @@ -463,6 +467,7 @@ 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, -- 2.27.0