On Wed, Jul 20, 2022 at 02:21:38PM +0100, Mark Cave-Ayland wrote: > On 20/07/2022 12:00, Roman Kagan wrote: > > > On Wed, Jul 20, 2022 at 11:44:26AM +0100, Daniel P. Berrangé wrote: > > > On Wed, Jul 20, 2022 at 01:25:55PM +0300, Roman Kagan wrote: > > > > It's possible to create non-working configurations by attaching a device > > > > to a derivative of PCIe slot (pcie-root-port, ioh3420, etc) and > > > > specifying a slot number other that zero, e.g.: > > > > > > > > -device pcie-root-port,id=s0,... \ > > > > -device virtio-blk-pci,bus=s0,addr=4,... > > > > > > > > Make QEMU reject such configurations and only allow addr=0 on the > > > > secondary bus of a PCIe slot. > > > > > > What do you mean by 'non-working' in this case. The guest OS boots > > > OK, but I indeed don't see the device in the guest, but IIUC it was > > > said that was just because Linux doesn't scan for a non-zero slot. > > > > Right. I don't remember if it was Linux or firmware or both but indeed > > at least Linux guests don't see devices if attached to a PCIe slot at > > addr != 0. (Which is kinda natural for a thing called "slot", isn't it?) > > > > > That wouldn't be a broken config from QEMU's POV though, merely a > > > guest OS limitation ? > > > > Strictly speaking it wouldn't, indeed. But we've had created such a > > configuration (due to a bug in our management layer) and spent > > non-negligible time trying to figure out why the attached device didn't > > appear in the guest. So I thought it made sense to reject a > > configuration which is known to confuse guests. Doesn't it? > > This does seem a bit odd. What does the output of "info qtree" look like for > your non-working configuration?
Sure: command line: # qemu-system-x86_64 \ -name test,debug-threads=on \ -msg timestamp=on \ -machine q35,sata=false,usb=off \ -accel kvm \ -cpu Haswell-noTSX \ -smp 4,sockets=1,cores=4,threads=1 \ -vga std \ -m 4096M \ -object memory-backend-memfd,id=mem0,size=4096M,share=on \ -numa node,memdev=mem0,cpus=0-3 \ -nodefaults \ -no-user-config \ -chardev stdio,id=mon0 \ -mon chardev=mon0,mode=readline \ -boot strict=on \ -device vmcoreinfo \ -device pvpanic \ -device qemu-xhci,id=usb0 \ -device usb-tablet,bus=usb0.0 \ -chardev socket,path=serial0.sock,logfile=serial0.log,id=charserial0,reconnect=1 \ -device isa-serial,chardev=charserial0,id=serial0 \ -chardev file,path=bios0.log,id=debugcon \ -device isa-debugcon,iobase=0x402,chardev=debugcon \ -device pcie-root-port,id=s0,slot=0,bus=pcie.0,addr=05.0,multifunction=on,io-reserve=0 \ -device pcie-root-port,id=s1,slot=1,bus=pcie.0,addr=05.1,multifunction=on,io-reserve=0 \ -device pcie-root-port,id=s2,slot=2,bus=pcie.0,addr=05.2,multifunction=on,io-reserve=0 \ -device pcie-root-port,id=s3,slot=3,bus=pcie.0,addr=05.3,multifunction=on,io-reserve=0 \ -drive format=qcow2,file=f34.qcow2,id=hdd0,if=none,aio=native,cache=directsync,discard=unmap \ -netdev user,id=netdev0,hostfwd=tcp::0-:22 \ -device virtio-net-pci,disable-legacy=off,netdev=netdev0,id=net0,bus=s1 \ -object iothread,id=iot0 \ -device virtio-blk-pci,disable-legacy=off,scsi=off,rerror=report,werror=report,id=vblk0,drive=hdd0,bus=s0,iothread=iot0,bootindex=1 \ -object iothread,id=iot2 \ -drive driver=null-co,size=64M,id=hdd2,if=none \ -device virtio-blk-pci,disable-legacy=off,scsi=off,rerror=report,werror=report,id=vblk2,drive=hdd2,bus=s2,iothread=iot2,num-queues=4,addr=4 \ -nographic qemu HMP: (qemu) info qtree bus: main-system-bus type System dev: ps2-mouse, id "" gpio-out "" 1 dev: ps2-kbd, id "" gpio-out "" 1 dev: hpet, id "" gpio-in "" 2 gpio-out "" 1 gpio-out "sysbus-irq" 32 timers = 3 (0x3) msi = false hpet-intcap = 16711940 (0xff0104) hpet-offset-saved = true mmio 00000000fed00000/0000000000000400 dev: kvm-ioapic, id "" gpio-in "" 24 gsi_base = 0 (0x0) mmio 00000000fec00000/0000000000001000 dev: q35-pcihost, id "" MCFG = 2952790016 (0xb0000000) pci-hole64-size = 34359738368 (32 GiB) short_root_bus = 0 (0x0) below-4g-mem-size = 2147483648 (2 GiB) above-4g-mem-size = 2147483648 (2 GiB) x-pci-hole64-fix = true x-config-reg-migration-enabled = true bypass-iommu = false bus: pcie.0 type PCIE dev: pcie-root-port, id "s3" x-migrate-msix = true bus-reserve = 4294967295 (0xffffffff) io-reserve = 0 (0 B) mem-reserve = 18446744073709551615 (16 EiB) pref32-reserve = 18446744073709551615 (16 EiB) pref64-reserve = 18446744073709551615 (16 EiB) x-speed = "16" x-width = "32" power_controller_present = true disable-acs = false chassis = 0 (0x0) slot = 3 (0x3) hotplug = true x-native-hotplug = true port = 0 (0x0) aer_log_max = 8 (0x8) addr = 05.3 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class PCI bridge, addr 00:05.3, pci id 1b36:000c (sub 0000:0000) bar 0: mem at 0xfea18000 [0xfea18fff] bus: s3 type PCIE dev: pcie-root-port, id "s2" x-migrate-msix = true bus-reserve = 4294967295 (0xffffffff) io-reserve = 0 (0 B) mem-reserve = 18446744073709551615 (16 EiB) pref32-reserve = 18446744073709551615 (16 EiB) pref64-reserve = 18446744073709551615 (16 EiB) x-speed = "16" x-width = "32" power_controller_present = true disable-acs = false chassis = 0 (0x0) slot = 2 (0x2) hotplug = true x-native-hotplug = true port = 0 (0x0) aer_log_max = 8 (0x8) addr = 05.2 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class PCI bridge, addr 00:05.2, pci id 1b36:000c (sub 0000:0000) bar 0: mem at 0xfea17000 [0xfea17fff] bus: s2 type PCIE dev: virtio-blk-pci, id "vblk2" disable-legacy = "off" disable-modern = false class = 0 (0x0) ioeventfd = true vectors = 5 (0x5) virtio-pci-bus-master-bug-migration = false migrate-extra = true modern-pio-notify = false x-disable-pcie = false page-per-vq = false x-ignore-backend-features = false ats = false x-ats-page-aligned = true x-pcie-deverr-init = true x-pcie-lnkctl-init = true x-pcie-pm-init = true x-pcie-flr-init = true aer = false addr = 04.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class SCSI controller, addr 03:04.0, pci id 1af4:1001 (sub 1af4:0002) bar 0: i/o at 0xffffffffffffffff [0x7e] bar 1: mem at 0xffffffffffffffff [0xffe] bar 4: mem at 0xffffffffffffffff [0x3ffe] bus: virtio-bus type virtio-pci-bus dev: virtio-blk-device, id "" drive = "hdd2" backend_defaults = "auto" logical_block_size = 512 (512 B) physical_block_size = 512 (512 B) min_io_size = 0 (0 B) opt_io_size = 0 (0 B) discard_granularity = 4294967295 (4 GiB) write-cache = "auto" share-rw = false rerror = "report" werror = "report" cyls = 130 (0x82) heads = 16 (0x10) secs = 63 (0x3f) lcyls = 0 (0x0) lheads = 0 (0x0) lsecs = 0 (0x0) serial = "" config-wce = true scsi = false request-merging = true num-queues = 4 (0x4) queue-size = 256 (0x100) seg-max-adjust = true discard = true report-discard-granularity = true write-zeroes = true max-discard-sectors = 4194303 (0x3fffff) max-write-zeroes-sectors = 4194303 (0x3fffff) x-enable-wce-if-config-wce = true indirect_desc = true event_idx = true notify_on_empty = true any_layout = true iommu_platform = false packed = false use-started = true use-disabled-flag = true x-disable-legacy-check = false dev: pcie-root-port, id "s1" x-migrate-msix = true bus-reserve = 4294967295 (0xffffffff) io-reserve = 0 (0 B) mem-reserve = 18446744073709551615 (16 EiB) pref32-reserve = 18446744073709551615 (16 EiB) pref64-reserve = 18446744073709551615 (16 EiB) x-speed = "16" x-width = "32" power_controller_present = true disable-acs = false chassis = 0 (0x0) slot = 1 (0x1) hotplug = true x-native-hotplug = true port = 0 (0x0) aer_log_max = 8 (0x8) addr = 05.1 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class PCI bridge, addr 00:05.1, pci id 1b36:000c (sub 0000:0000) bar 0: mem at 0xfea16000 [0xfea16fff] bus: s1 type PCIE dev: virtio-net-pci, id "net0" disable-legacy = "off" disable-modern = false ioeventfd = true vectors = 4 (0x4) virtio-pci-bus-master-bug-migration = false migrate-extra = true modern-pio-notify = false x-disable-pcie = false page-per-vq = false x-ignore-backend-features = false ats = false x-ats-page-aligned = true x-pcie-deverr-init = true x-pcie-lnkctl-init = true x-pcie-pm-init = true x-pcie-flr-init = true aer = false addr = 00.0 romfile = "efi-virtio.rom" romsize = 262144 (0x40000) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class Ethernet controller, addr 02:00.0, pci id 1af4:1000 (sub 1af4:0001) bar 0: i/o at 0x2000 [0x201f] bar 1: mem at 0xfe640000 [0xfe640fff] bar 4: mem at 0xfd400000 [0xfd403fff] bar 6: mem at 0xffffffffffffffff [0x3fffe] bus: virtio-bus type virtio-pci-bus dev: virtio-net-device, id "" csum = true guest_csum = true gso = true guest_tso4 = true guest_tso6 = true guest_ecn = true guest_ufo = true guest_announce = true host_tso4 = true host_tso6 = true host_ecn = true host_ufo = true mrg_rxbuf = true status = true ctrl_vq = true ctrl_rx = true ctrl_vlan = true ctrl_rx_extra = true ctrl_mac_addr = true ctrl_guest_offloads = true mq = false rss = false hash = false guest_rsc_ext = false rsc_interval = 300000 (0x493e0) mac = "52:54:00:12:34:56" netdev = "netdev0" x-txtimer = 150000 (0x249f0) x-txburst = 256 (0x100) tx = "" rx_queue_size = 256 (0x100) tx_queue_size = 256 (0x100) host_mtu = 0 (0x0) x-mtu-bypass-backend = true speed = -1 (0xffffffffffffffff) duplex = "" failover = false indirect_desc = true event_idx = true notify_on_empty = true any_layout = true iommu_platform = false packed = false use-started = true use-disabled-flag = true x-disable-legacy-check = false dev: pcie-root-port, id "s0" x-migrate-msix = true bus-reserve = 4294967295 (0xffffffff) io-reserve = 0 (0 B) mem-reserve = 18446744073709551615 (16 EiB) pref32-reserve = 18446744073709551615 (16 EiB) pref64-reserve = 18446744073709551615 (16 EiB) x-speed = "16" x-width = "32" power_controller_present = true disable-acs = false chassis = 0 (0x0) slot = 0 (0x0) hotplug = true x-native-hotplug = true port = 0 (0x0) aer_log_max = 8 (0x8) addr = 05.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class PCI bridge, addr 00:05.0, pci id 1b36:000c (sub 0000:0000) bar 0: mem at 0xfea15000 [0xfea15fff] bus: s0 type PCIE dev: virtio-blk-pci, id "vblk0" disable-legacy = "off" disable-modern = false class = 0 (0x0) ioeventfd = true vectors = 5 (0x5) virtio-pci-bus-master-bug-migration = false migrate-extra = true modern-pio-notify = false x-disable-pcie = false page-per-vq = false x-ignore-backend-features = false ats = false x-ats-page-aligned = true x-pcie-deverr-init = true x-pcie-lnkctl-init = true x-pcie-pm-init = true x-pcie-flr-init = true aer = false addr = 00.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class SCSI controller, addr 01:00.0, pci id 1af4:1001 (sub 1af4:0002) bar 0: i/o at 0x1000 [0x107f] bar 1: mem at 0xfe800000 [0xfe800fff] bar 4: mem at 0xfd600000 [0xfd603fff] bus: virtio-bus type virtio-pci-bus dev: virtio-blk-device, id "" drive = "hdd0" backend_defaults = "auto" logical_block_size = 512 (512 B) physical_block_size = 512 (512 B) min_io_size = 0 (0 B) opt_io_size = 0 (0 B) discard_granularity = 4294967295 (4 GiB) write-cache = "auto" share-rw = false rerror = "report" werror = "report" cyls = 10402 (0x28a2) heads = 16 (0x10) secs = 63 (0x3f) lcyls = 0 (0x0) lheads = 0 (0x0) lsecs = 0 (0x0) serial = "" config-wce = true scsi = false request-merging = true num-queues = 4 (0x4) queue-size = 256 (0x100) seg-max-adjust = true discard = true report-discard-granularity = true write-zeroes = true max-discard-sectors = 4194303 (0x3fffff) max-write-zeroes-sectors = 4194303 (0x3fffff) x-enable-wce-if-config-wce = true indirect_desc = true event_idx = true notify_on_empty = true any_layout = true iommu_platform = false packed = false use-started = true use-disabled-flag = true x-disable-legacy-check = false dev: qemu-xhci, id "usb0" addr = 02.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class USB controller, addr 00:02.0, pci id 1b36:000d (sub 1af4:1100) bar 0: mem at 0xfea10000 [0xfea13fff] bus: usb0.0 type usb-bus dev: usb-tablet, id "" usb_version = 2 (0x2) display = "" head = 0 (0x0) port = "" serial = "" msos-desc = true pcap = "" addr 0.1, port 1, speed 480, name QEMU USB Tablet, attached dev: VGA, id "" vgamem_mb = 16 (0x10) mmio = true qemu-extended-regs = true edid = true xres = 1280 (0x500) yres = 800 (0x320) xmax = 0 (0x0) ymax = 0 (0x0) refresh_rate = 0 (0x0) global-vmstate = false addr = 01.0 romfile = "vgabios-stdvga.bin" romsize = 65536 (0x10000) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class VGA controller, addr 00:01.0, pci id 1234:1111 (sub 1af4:1100) bar 0: mem at 0xfc000000 [0xfcffffff] bar 2: mem at 0xfea14000 [0xfea14fff] bar 6: mem at 0xffffffffffffffff [0xfffe] dev: ICH9-SMB, id "" addr = 1f.3 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class SMBus, addr 00:1f.3, pci id 8086:2930 (sub 1af4:1100) bar 4: i/o at 0x700 [0x73f] bus: i2c type i2c-bus dev: smbus-eeprom, id "" address = 87 (0x57) dev: smbus-eeprom, id "" address = 86 (0x56) dev: smbus-eeprom, id "" address = 85 (0x55) dev: smbus-eeprom, id "" address = 84 (0x54) dev: smbus-eeprom, id "" address = 83 (0x53) dev: smbus-eeprom, id "" address = 82 (0x52) dev: smbus-eeprom, id "" address = 81 (0x51) dev: smbus-eeprom, id "" address = 80 (0x50) dev: ICH9-LPC, id "" gpio-out "gsi" 24 noreboot = true smm-compat = false x-smi-broadcast = true x-smi-cpu-hotplug = true x-smi-cpu-hotunplug = true addr = 1f.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = true x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class ISA bridge, addr 00:1f.0, pci id 8086:2918 (sub 1af4:1100) bus: isa.0 type ISA dev: isa-debugcon, id "" iobase = 1026 (0x402) chardev = "debugcon" readback = 233 (0xe9) dev: isa-serial, id "serial0" index = 0 (0x0) iobase = 1016 (0x3f8) irq = 4 (0x4) dev: pvpanic, id "" ioport = 1285 (0x505) events = 3 (0x3) dev: port92, id "" gpio-out "a20" 1 dev: vmmouse, id "" dev: vmport, id "" x-read-set-eax = true x-signal-unsupported-cmd = true x-report-vmx-type = true x-cmds-v2 = true vmware-vmx-version = 6 (0x6) vmware-vmx-type = 2 (0x2) dev: i8042, id "" gpio-in "ps2-mouse-input-irq" 1 gpio-in "ps2-kbd-input-irq" 1 gpio-out "" 2 gpio-out "a20" 1 extended-state = true kbd-throttle = false kbd-irq = 1 (0x1) mouse-irq = 12 (0xc) dev: i8257, id "" base = 192 (0xc0) page-base = 136 (0x88) pageh-base = -1 (0xffffffffffffffff) dshift = 1 (0x1) dev: i8257, id "" base = 0 (0x0) page-base = 128 (0x80) pageh-base = -1 (0xffffffffffffffff) dshift = 0 (0x0) dev: isa-pcspk, id "" audiodev = "" iobase = 97 (0x61) migrate = true dev: kvm-pit, id "" gpio-in "" 1 iobase = 64 (0x40) lost_tick_policy = "delay" dev: mc146818rtc, id "" gpio-out "" 1 base_year = 0 (0x0) iobase = 112 (0x70) irq = 8 (0x8) lost_tick_policy = "discard" dev: kvm-i8259, id "" iobase = 160 (0xa0) elcr_addr = 1233 (0x4d1) elcr_mask = 222 (0xde) master = false dev: kvm-i8259, id "" iobase = 32 (0x20) elcr_addr = 1232 (0x4d0) elcr_mask = 248 (0xf8) master = true dev: mch, id "" extended-tseg-mbytes = 16 (0x10) smbase-smram = true addr = 00.0 romfile = "" romsize = 4294967295 (0xffffffff) rombar = 1 (0x1) multifunction = false x-pcie-lnksta-dllla = true x-pcie-extcap-init = true failover_pair_id = "" acpi-index = 0 (0x0) class Host bridge, addr 00:00.0, pci id 8086:29c0 (sub 1af4:1100) dev: fw_cfg_io, id "" dma_enabled = true x-file-slots = 32 (0x20) acpi-mr-restore = true dev: kvmclock, id "" x-mach-use-reliable-get-clock = true dev: kvmvapic, id "" (qemu) info pci Bus 0, device 0, function 0: Host bridge: PCI device 8086:29c0 PCI subsystem 1af4:1100 id "" Bus 0, device 1, function 0: VGA controller: PCI device 1234:1111 PCI subsystem 1af4:1100 BAR0: 32 bit prefetchable memory at 0xfc000000 [0xfcffffff]. BAR2: 32 bit memory at 0xfea14000 [0xfea14fff]. BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe]. id "" Bus 0, device 2, function 0: USB controller: PCI device 1b36:000d PCI subsystem 1af4:1100 IRQ 11, pin A BAR0: 64 bit memory at 0xfea10000 [0xfea13fff]. id "usb0" Bus 0, device 5, function 0: PCI bridge: PCI device 1b36:000c IRQ 10, pin A BUS 0. secondary bus 1. subordinate bus 1. IO range [0xf000, 0x0fff] memory range [0xfe800000, 0xfe9fffff] prefetchable memory range [0xfd600000, 0xfd7fffff] BAR0: 32 bit memory at 0xfea15000 [0xfea15fff]. id "s0" Bus 1, device 0, function 0: SCSI controller: PCI device 1af4:1001 PCI subsystem 1af4:0002 IRQ 10, pin A BAR0: I/O at 0x1000 [0x107f]. BAR1: 32 bit memory at 0xfe800000 [0xfe800fff]. BAR4: 64 bit prefetchable memory at 0xfd600000 [0xfd603fff]. id "vblk0" Bus 0, device 5, function 1: PCI bridge: PCI device 1b36:000c IRQ 10, pin A BUS 0. secondary bus 2. subordinate bus 2. IO range [0xf000, 0x0fff] memory range [0xfe600000, 0xfe7fffff] prefetchable memory range [0xfd400000, 0xfd5fffff] BAR0: 32 bit memory at 0xfea16000 [0xfea16fff]. id "s1" Bus 2, device 0, function 0: Ethernet controller: PCI device 1af4:1000 PCI subsystem 1af4:0001 IRQ 10, pin A BAR0: I/O at 0x2000 [0x201f]. BAR1: 32 bit memory at 0xfe640000 [0xfe640fff]. BAR4: 64 bit prefetchable memory at 0xfd400000 [0xfd403fff]. BAR6: 32 bit memory at 0xffffffffffffffff [0x0003fffe]. id "net0" Bus 0, device 5, function 2: PCI bridge: PCI device 1b36:000c IRQ 10, pin A BUS 0. secondary bus 3. subordinate bus 3. IO range [0xf000, 0x0fff] memory range [0xfe400000, 0xfe5fffff] prefetchable memory range [0xfd200000, 0xfd3fffff] BAR0: 32 bit memory at 0xfea17000 [0xfea17fff]. id "s2" Bus 3, device 4, function 0: SCSI controller: PCI device 1af4:1001 PCI subsystem 1af4:0002 IRQ 0, pin A BAR0: I/O at 0xffffffffffffffff [0x007e]. BAR1: 32 bit memory at 0xffffffffffffffff [0x00000ffe]. BAR4: 64 bit prefetchable memory at 0xffffffffffffffff [0x00003ffe]. id "vblk2" Bus 0, device 5, function 3: PCI bridge: PCI device 1b36:000c IRQ 10, pin A BUS 0. secondary bus 4. subordinate bus 4. IO range [0xf000, 0x0fff] memory range [0xfe200000, 0xfe3fffff] prefetchable memory range [0xfd000000, 0xfd1fffff] BAR0: 32 bit memory at 0xfea18000 [0xfea18fff]. id "s3" Bus 0, device 31, function 0: ISA bridge: PCI device 8086:2918 PCI subsystem 1af4:1100 id "" Bus 0, device 31, function 3: SMBus: PCI device 8086:2930 PCI subsystem 1af4:1100 IRQ 10, pin A BAR4: I/O at 0x0700 [0x073f]. id "" In the guest (Fedora 34): [root@test ~]# lspci -tv -[0000:00]-+-00.0 Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller +-01.0 Device 1234:1111 +-02.0 Red Hat, Inc. QEMU XHCI Host Controller +-05.0-[01]----00.0 Red Hat, Inc. Virtio block device +-05.1-[02]----00.0 Red Hat, Inc. Virtio network device +-05.2-[03]-- +-05.3-[04]-- +-1f.0 Intel Corporation 82801IB (ICH9) LPC Interface Controller \-1f.3 Intel Corporation 82801I (ICH9 Family) SMBus Controller Changing addr of the second disk from 4 to 0 makes it appear in the guest. What exactly do you find odd? Thanks, Roman.