Memory Ballooning device crashes host kernel on device-passthrough branch

[rmohr]

I started a TDX guest with QEMU from device-passthrough and the KVM patches for the host and had by accident still the virtio balloon device attached:

-device '{\"driver\":\"virtio-balloon-pci-non-transitional\",\"id\":\"balloon0\",\"free-page-reporting\":true,\"bus\":\"pci.9\",\"addr\":\"0x0\"}'

I could not retrieve a kernel dump at this point, but it reliably crashes the host kernel. Maybe worth reproducing and fixing. I would expect that the guest fails to start instead of the host crashing.

[dujh]

Thanks for the suggestion! We will look into it and propose a fix if necessary.

[Qiangcy]

I manually add the virtio-balloon-pci device in qemu command to launch a TD but cannot reproduce the issue. virtio-balloon is just not working with the dmesg info "device must provide VIRTIO_F_ACCESS_PLATFORM". But the host doesn't crash. Can you provide more details on how to reproduce it?

[rmohr]

Hm, it failed for me on this commit: https://github.com/intel/tdx-linux/tree/1323f7b1ddf81076e3fcda6385c0c0dcf506258c/tdx-qemu maybe that helps.

The full commandline was somewhat like this:

/usr/bin/qemu-system-x86_64 -name guest=default_vmi-nocloud,debug-threads=on -S -object '{\"qom-type\":\"secret\",\"id\":\"masterKey0\",\"format\":\"raw\",\"file\":\"/var/lib/libvirt/qemu/domain-10-default_vmi-nocloud/master-key.aes\"}' -machine pc-q35-9.1,usb=off,dump-guest-core=off,memory-backend=pc.ram,acpi=on -accel kvm -cpu host,migratable=on,kvmclock=off -bios /usr/share/OVMF/OVMF_CODE.fd -m size=131072k -object '{\"qom-type\":\"memory-backend-ram\",\"id\":\"pc.ram\",\"size\":134217728}' -overcommit mem-lock=off -smp 1,sockets=1,dies=1,clusters=1,cores=1,threads=1 -object '{\"qom-type\":\"iothread\",\"id\":\"iothread1\"}' -uuid 31a4f71e-39f7-4f58-b771-4f3f33fb46ae -smbios type=1,manufacturer=KubeVirt,product=None,uuid=31a4f71e-39f7-4f58-b771-4f3f33fb46ae,family=KubeVirt -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=21,server=on,wait=off -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device '{\"driver\":\"pcie-root-port\",\"port\":16,\"chassis\":1,\"id\":\"pci.1\",\"bus\":\"pcie.0\",\"multifunction\":true,\"addr\":\"0x2\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":17,\"chassis\":2,\"id\":\"pci.2\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x1\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":18,\"chassis\":3,\"id\":\"pci.3\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x2\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":19,\"chassis\":4,\"id\":\"pci.4\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x3\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":20,\"chassis\":5,\"id\":\"pci.5\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x4\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":21,\"chassis\":6,\"id\":\"pci.6\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x5\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":22,\"chassis\":7,\"id\":\"pci.7\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x6\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":23,\"chassis\":8,\"id\":\"pci.8\",\"bus\":\"pcie.0\",\"addr\":\"0x2.0x7\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":24,\"chassis\":9,\"id\":\"pci.9\",\"bus\":\"pcie.0\",\"multifunction\":true,\"addr\":\"0x3\"}' -device '{\"driver\":\"pcie-root-port\",\"port\":25,\"chassis\":10,\"id\":\"pci.10\",\"bus\":\"pcie.0\",\"addr\":\"0x3.0x1\"}' -device '{\"driver\":\"virtio-scsi-pci-non-transitional\",\"id\":\"scsi0\",\"bus\":\"pci.5\",\"addr\":\"0x0\"}' -device '{\"driver\":\"virtio-serial-pci-non-transitional\",\"id\":\"virtio-serial0\",\"bus\":\"pci.6\",\"addr\":\"0x0\"}' -blockdev '{\"driver\":\"file\",\"filename\":\"/var/run/kubevirt-ephemeral-disks/cloud-init-data/default/vmi-nocloud/noCloud.iso\",\"aio\":\"native\",\"node-name\":\"libvirt-2-storage\",\"read-only\":false,\"discard\":\"unmap\",\"cache\":{\"direct\":true,\"no-flush\":false}}' -device '{\"driver\":\"virtio-blk-pci-non-transitional\",\"bus\":\"pci.7\",\"addr\":\"0x0\",\"drive\":\"libvirt-2-storage\",\"id\":\"ua-cloudinitdisk\",\"bootindex\":1,\"write-cache\":\"on\",\"werror\":\"stop\",\"rerror\":\"stop\"}' -blockdev '{\"driver\":\"file\",\"filename\":\"/var/run/libvirt/empty-disks/emptydisk.qcow2\",\"aio\":\"native\",\"node-name\":\"libvirt-1-storage\",\"auto-read-only\":true,\"discard\":\"unmap\",\"cache\":{\"direct\":true,\"no-flush\":false}}' -blockdev '{\"node-name\":\"libvirt-1-format\",\"read-only\":false,\"discard\":\"unmap\",\"cache\":{\"direct\":true,\"no-flush\":false},\"driver\":\"qcow2\",\"file\":\"libvirt-1-storage\",\"backing\":null}' -device '{\"driver\":\"virtio-blk-pci-non-transitional\",\"bus\":\"pci.8\",\"addr\":\"0x0\",\"drive\":\"libvirt-1-format\",\"id\":\"ua-emptydisk\",\"write-cache\":\"on\",\"werror\":\"stop\",\"rerror\":\"stop\"}' -netdev '{\"type\":\"tap\",\"fd\":\"22\",\"vhost\":true,\"vhostfd\":\"24\",\"id\":\"hostua-default\"}' -device '{\"driver\":\"virtio-net-pci-non-transitional\",\"host_mtu\":1450,\"netdev\":\"hostua-default\",\"id\":\"ua-default\",\"mac\":\"5e:ed:b5:fd:59:3e\",\"bus\":\"pci.1\",\"addr\":\"0x0\",\"romfile\":\"\"}' -add-fd set=0,fd=20,opaque=serial0-log -chardev socket,id=charserial0,fd=18,server=on,wait=off,logfile=/dev/fdset/0,logappend=on -device '{\"driver\":\"isa-serial\",\"chardev\":\"charserial0\",\"id\":\"serial0\",\"index\":0}' -chardev socket,id=charchannel0,fd=19,server=on,wait=off -device '{\"driver\":\"virtserialport\",\"bus\":\"virtio-serial0.0\",\"nr\":1,\"chardev\":\"charchannel0\",\"id\":\"channel0\",\"name\":\"org.qemu.guest_agent.0\"}' -audiodev '{\"id\":\"audio1\",\"driver\":\"none\"}' -vnc vnc=unix:/var/run/kubevirt-private/4b9e3652-f663-4dfb-aa31-5dfdf5bcce51/virt-vnc,audiodev=audio1 -device '{\"driver\":\"VGA\",\"id\":\"video0\",\"vgamem_mb\":16,\"bus\":\"pcie.0\",\"addr\":\"0x1\"}' -global ICH9-LPC.noreboot=off -watchdog-action reset -device '{\"driver\":\"virtio-balloon-pci-non-transitional\",\"id\":\"balloon0\",\"free-page-reporting\":true,\"bus\":\"pci.9\",\"addr\":\"0x0\"}' -machine q35,memory-backend=pc.ram,kernel-irqchip=split,confidential-guest-support=tdx -object '{\"qom-type\":\"tdx-guest\",\"id\":\"tdx\",\"quote-generation-socket\":{\"type\": \"vsock\", \"cid\":\"2\",\"port\":\"4050\"}}' -fw_cfg name=opt/ovmf/X-PciMmio64,string=262144 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on

[Qiangcy]

Sorry to miss this issue. Since your commits were out-of-date, are you still able to reproduce this issue with upstream tree?