Public bug reported: I'm seeing some errors when assigning my NVMe disk to qemu. This is the full command line:
/home/zippy/work/qemu/qemu.git/x86_64-softmmu/qemu-system-x86_64 \ -name guest=fedora,debug-threads=on \ -S \ -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-fedora/master-key.aes \ -machine pc-i440fx-4.1,accel=kvm,usb=off,dump-guest-core=off \ -cpu host \ -m size=4194304k,slots=16,maxmem=1099511627776k \ -overcommit mem-lock=off \ -smp 4,sockets=1,dies=1,cores=2,threads=2 \ -object iothread,id=iothread1 \ -object iothread,id=iothread2 \ -object iothread,id=iothread3 \ -object iothread,id=iothread4 \ -mem-prealloc \ -mem-path /hugepages2M/libvirt/qemu/2-fedora \ -numa node,nodeid=0,cpus=0,mem=4096 \ -uuid 63840878-0deb-4095-97e6-fc444d9bc9fa \ -no-user-config \ -nodefaults \ -chardev socket,id=charmonitor,fd=31,server,nowait \ -mon chardev=charmonitor,id=monitor,mode=control \ -rtc base=utc \ -no-shutdown \ -global PIIX4_PM.disable_s3=0 \ -global PIIX4_PM.disable_s4=0 \ -boot menu=on,strict=on \ -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \ -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4 \ -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 \ -blockdev '{"driver":"file","filename":"/var/lib/libvirt/images/fedora.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \ -blockdev '{"node-name":"libvirt-2-format","read-only":false,"discard":"unmap","driver":"qcow2","file":"libvirt-2-storage","backing":null}' \ -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,device_id=drive-scsi0-0-0-0,drive=libvirt-2-format,id=scsi0-0-0-0,bootindex=1 \ -blockdev '{"driver":"nvme","device":"0000:02:00.0","namespace":1,"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \ -blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"raw","file":"libvirt-1-storage"}' \ -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=libvirt-1-format,id=virtio-disk0 \ -netdev tap,fd=33,id=hostnet0,vhost=on,vhostfd=34 \ -device virtio-net-pci,host_mtu=9000,netdev=hostnet0,id=net0,mac=52:54:00:a4:6f:91,bus=pci.0,addr=0x3 \ -chardev pty,id=charserial0 \ -device isa-serial,chardev=charserial0,id=serial0 \ -chardev socket,id=charchannel0,fd=35,server,nowait \ -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 \ -spice port=5900,addr=0.0.0.0,disable-ticketing,seamless-migration=on \ -device virtio-vga,id=video0,virgl=on,max_outputs=1,bus=pci.0,addr=0x2 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 \ -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \ -msg timestamp=on And these are the errors I see: 2020-02-14T09:06:18.183167Z qemu-system-x86_64: VFIO_MAP_DMA failed: Invalid argument 2020-02-14T09:10:49.753767Z qemu-system-x86_64: VFIO_MAP_DMA failed: Cannot allocate memory 2020-02-14T09:11:04.530344Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device 2020-02-14T09:11:04.531087Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device 2020-02-14T09:11:04.531230Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device I'm doing nothing with the disk inside the guest, but: # dd if=/dev/vda of=/dev/null status=progress (the disk appears as /dev/vda in the guest). Surprisingly, I do not see these errors when I use the traditional PCI assignment (-device vfio- pci). My versions of kernel and qemu: moe ~ # uname -r 5.4.15-gentoo moe ~ # /home/zippy/work/qemu/qemu.git/x86_64-softmmu/qemu-system-x86_64 --version QEMU emulator version 4.2.50 (v4.2.0-1439-g5d6542bea7-dirty) Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers ** Affects: qemu Importance: Undecided Status: New -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1863333 Title: Assigning NVMe disk to a domain causes VFIO_MAP_DMA errors Status in QEMU: New Bug description: I'm seeing some errors when assigning my NVMe disk to qemu. This is the full command line: /home/zippy/work/qemu/qemu.git/x86_64-softmmu/qemu-system-x86_64 \ -name guest=fedora,debug-threads=on \ -S \ -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-fedora/master-key.aes \ -machine pc-i440fx-4.1,accel=kvm,usb=off,dump-guest-core=off \ -cpu host \ -m size=4194304k,slots=16,maxmem=1099511627776k \ -overcommit mem-lock=off \ -smp 4,sockets=1,dies=1,cores=2,threads=2 \ -object iothread,id=iothread1 \ -object iothread,id=iothread2 \ -object iothread,id=iothread3 \ -object iothread,id=iothread4 \ -mem-prealloc \ -mem-path /hugepages2M/libvirt/qemu/2-fedora \ -numa node,nodeid=0,cpus=0,mem=4096 \ -uuid 63840878-0deb-4095-97e6-fc444d9bc9fa \ -no-user-config \ -nodefaults \ -chardev socket,id=charmonitor,fd=31,server,nowait \ -mon chardev=charmonitor,id=monitor,mode=control \ -rtc base=utc \ -no-shutdown \ -global PIIX4_PM.disable_s3=0 \ -global PIIX4_PM.disable_s4=0 \ -boot menu=on,strict=on \ -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \ -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4 \ -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 \ -blockdev '{"driver":"file","filename":"/var/lib/libvirt/images/fedora.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \ -blockdev '{"node-name":"libvirt-2-format","read-only":false,"discard":"unmap","driver":"qcow2","file":"libvirt-2-storage","backing":null}' \ -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,device_id=drive-scsi0-0-0-0,drive=libvirt-2-format,id=scsi0-0-0-0,bootindex=1 \ -blockdev '{"driver":"nvme","device":"0000:02:00.0","namespace":1,"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \ -blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"raw","file":"libvirt-1-storage"}' \ -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=libvirt-1-format,id=virtio-disk0 \ -netdev tap,fd=33,id=hostnet0,vhost=on,vhostfd=34 \ -device virtio-net-pci,host_mtu=9000,netdev=hostnet0,id=net0,mac=52:54:00:a4:6f:91,bus=pci.0,addr=0x3 \ -chardev pty,id=charserial0 \ -device isa-serial,chardev=charserial0,id=serial0 \ -chardev socket,id=charchannel0,fd=35,server,nowait \ -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 \ -spice port=5900,addr=0.0.0.0,disable-ticketing,seamless-migration=on \ -device virtio-vga,id=video0,virgl=on,max_outputs=1,bus=pci.0,addr=0x2 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 \ -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \ -msg timestamp=on And these are the errors I see: 2020-02-14T09:06:18.183167Z qemu-system-x86_64: VFIO_MAP_DMA failed: Invalid argument 2020-02-14T09:10:49.753767Z qemu-system-x86_64: VFIO_MAP_DMA failed: Cannot allocate memory 2020-02-14T09:11:04.530344Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device 2020-02-14T09:11:04.531087Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device 2020-02-14T09:11:04.531230Z qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device I'm doing nothing with the disk inside the guest, but: # dd if=/dev/vda of=/dev/null status=progress (the disk appears as /dev/vda in the guest). Surprisingly, I do not see these errors when I use the traditional PCI assignment (-device vfio-pci). My versions of kernel and qemu: moe ~ # uname -r 5.4.15-gentoo moe ~ # /home/zippy/work/qemu/qemu.git/x86_64-softmmu/qemu-system-x86_64 --version QEMU emulator version 4.2.50 (v4.2.0-1439-g5d6542bea7-dirty) Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1863333/+subscriptions