QEMU host-only networking using tap devices

Question

I'm trying to setup host-only networking on my QEMU VM running Arch (actually, the Archiso; there is no Arch installation present yet). A short summary:
What I want
connect to the host from the guest system
connect to the guest from the host system
using a tap device (to avoid user-mode networking) on a network bridge (to connect guest and host)
Eventually, I want to run an AMP stack on the VM for web development. (Let's, for now, ignore the fact that I might need an internet connection later on to install packages)
What I tried
I first set up a tap device:
ip tuntap add dev tap0 mode tap
and then a network bridge:
BRIDGE='qemubr0'
brctl addbr ${BRIDGE}
brctl addif ${BRIDGE} tap0
ip link set up dev ${BRIDGE}
The relevant parameters I run QEMU with are:
qemu-system-x86_64 \
-net nic \
-net tap,ifname=tap0,script=no
QEMU starts without any errors, but trying to ping the host from within the VM results in:
-- VM:
# ping 10.0.2.2
connect: Network is unreachable
(FYI: 10.0.2.2 is supposed to be the default IP address of the host system (?) according to http://wiki.qemu.org/Documentation/Networking )
Relevant logs/outputs
dmesg on the host machine:
[ 0.339337] NET: Registered protocol family 2
[ 0.339670] TCP established hash table entries: 32768 (order: 6, 262144 bytes)
[ 0.339851] TCP bind hash table entries: 32768 (order: 7, 524288 bytes)
[ 0.340102] TCP: Hash tables configured (established 32768 bind 32768)
[ 0.340171] TCP: reno registered
[ 0.340182] UDP hash table entries: 2048 (order: 4, 65536 bytes)
[ 0.340226] UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes)
[ 0.340327] NET: Registered protocol family 1
[ 0.340353] pci 0000:00:02.0: Video device with shadowed ROM
[ 0.341863] PCI: CLS 64 bytes, default 64
[ 0.341937] Unpacking initramfs...
[ 0.503984] Freeing initrd memory: 4908K (ffff88003765a000 - ffff880037b25000)
[ 0.504055] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 0.504060] software IO TLB [mem 0xb94a1000-0xbd4a1000] (64MB) mapped at [ffff8800b94a1000-ffff8800bd4a0fff]
[ 0.504112] Simple Boot Flag at 0x35 set to 0x1
[ 0.504352] microcode: CPU0 sig=0x1067a, pf=0x80, revision=0xa0c
[ 0.504364] microcode: CPU1 sig=0x1067a, pf=0x80, revision=0xa0c
[ 0.504475] microcode: Microcode Update Driver: v2.00 <[email protected]>, Peter Oruba
[ 0.504524] Scanning for low memory corruption every 60 seconds
[ 0.505041] futex hash table entries: 1024 (order: 4, 65536 bytes)
[ 0.505090] Initialise system trusted keyring
[ 0.505685] HugeTLB registered 2 MB page size, pre-allocated 0 pages
[ 0.508836] zpool: loaded
[ 0.508841] zbud: loaded
[ 0.509100] VFS: Disk quotas dquot_6.5.2
[ 0.509170] Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[ 0.509392] msgmni has been set to 7699
[ 0.509494] Key type big_key registered
[ 0.509767] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[ 0.509826] io scheduler noop registered
[ 0.509830] io scheduler deadline registered
[ 0.509893] io scheduler cfq registered (default)
[ 0.510198] pcieport 0000:00:1c.0: irq 24 for MSI/MSI-X
[ 0.510482] pcieport 0000:00:1c.1: irq 25 for MSI/MSI-X
[ 0.510705] pcieport 0000:00:1c.0: Signaling PME through PCIe PME interrupt
[ 0.510713] pcie_pme 0000:00:1c.0:pcie01: service driver pcie_pme loaded
[ 0.510744] pcieport 0000:00:1c.1: Signaling PME through PCIe PME interrupt
[ 0.510748] pci 0000:03:00.0: Signaling PME through PCIe PME interrupt
[ 0.510754] pcie_pme 0000:00:1c.1:pcie01: service driver pcie_pme loaded
[ 0.510785] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[ 0.510847] pciehp 0000:00:1c.0:pcie04: Slot #0 AttnBtn- AttnInd- PwrInd- PwrCtrl- MRL- Interlock- NoCompl- LLActRep+
[ 1.506690] tsc: Refined TSC clocksource calibration: 1396.499 MHz
[ 1.843356] pciehp 0000:00:1c.0:pcie04: Timeout on hotplug command 0x00000000 (issued 1333 msec ago)
[ 1.843368] pciehp 0000:00:1c.0:pcie04: service driver pciehp loaded
[ 1.843390] pciehp 0000:00:1c.1:pcie04: Slot #1 AttnBtn- AttnInd- PwrInd- PwrCtrl- MRL- Interlock- NoCompl- LLActRep+
[ 2.506739] Switched to clocksource tsc
[ 3.176680] pciehp 0000:00:1c.1:pcie04: Timeout on hotplug command 0x00000000 (issued 1333 msec ago)
[ 3.176691] pciehp 0000:00:1c.1:pcie04: service driver pciehp loaded
[ 3.176703] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
[ 3.176768] vesafb: mode is 1440x900x32, linelength=5760, pages=0
[ 3.176770] vesafb: scrolling: redraw
[ 3.176774] vesafb: Truecolor: size=8:8:8:8, shift=24:16:8:0
[ 3.176807] vesafb: framebuffer at 0xd0000000, mapped to 0xffffc90004780000, using 5120k, total 5120k
[ 3.235921] Console: switching to colour frame buffer device 180x56
[ 3.294769] fb0: VESA VGA frame buffer device
[ 3.294803] intel_idle: does not run on family 6 model 23
[ 3.294882] GHES: HEST is not enabled!
[ 3.294990] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[ 3.316009] 0000:00:03.3: ttyS0 at I/O 0x1830 (irq = 17, base_baud = 115200) is a 16550A
[ 3.316238] Linux agpgart interface v0.103
[ 3.316307] rtc_cmos 00:02: RTC can wake from S4
[ 3.316496] rtc_cmos 00:02: rtc core: registered rtc_cmos as rtc0
[ 3.316535] rtc_cmos 00:02: alarms up to one month, y3k, 114 bytes nvram, hpet irqs
[ 3.316560] ledtrig-cpu: registered to indicate activity on CPUs
[ 3.316751] TCP: cubic registered
[ 3.316954] NET: Registered protocol family 10
[ 3.317338] NET: Registered protocol family 17
[ 3.317735] Loading compiled-in X.509 certificates
[ 3.317757] registered taskstats version 1
[ 3.318307] Magic number: 15:252:84
[ 3.318413] rtc_cmos 00:02: setting system clock to 2015-01-01 16:05:44 UTC (1420128344)
[ 3.318617] PM: Hibernation image not present or could not be loaded.
[ 3.320772] Freeing unused kernel memory: 1136K (ffffffff818e2000 - ffffffff819fe000)
[ 3.320775] Write protecting the kernel read-only data: 8192k
[ 3.324495] Freeing unused kernel memory: 748K (ffff880001545000 - ffff880001600000)
[ 3.326086] Freeing unused kernel memory: 336K (ffff8800017ac000 - ffff880001800000)
[ 3.336977] random: systemd-tmpfile urandom read with 4 bits of entropy available
[ 3.363462] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
[ 3.372761] serio: i8042 KBD port at 0x60,0x64 irq 1
[ 3.372934] serio: i8042 AUX port at 0x60,0x64 irq 12
[ 3.379297] ACPI: bus type USB registered
[ 3.379343] usbcore: registered new interface driver usbfs
[ 3.379364] usbcore: registered new interface driver hub
[ 3.380595] usbcore: registered new device driver usb
[ 3.381344] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 3.381800] uhci_hcd: USB Universal Host Controller Interface driver
[ 3.381991] uhci_hcd 0000:00:1a.0: UHCI Host Controller
[ 3.382003] uhci_hcd 0000:00:1a.0: new USB bus registered, assigned bus number 1
[ 3.382015] uhci_hcd 0000:00:1a.0: detected 2 ports
[ 3.382060] uhci_hcd 0000:00:1a.0: irq 20, io base 0x00001840
[ 3.382412] hub 1-0:1.0: USB hub found
[ 3.382427] hub 1-0:1.0: 2 ports detected
[ 3.383010] uhci_hcd 0000:00:1a.1: UHCI Host Controller
[ 3.383021] uhci_hcd 0000:00:1a.1: new USB bus registered, assigned bus number 2
[ 3.383032] uhci_hcd 0000:00:1a.1: detected 2 ports
[ 3.383073] uhci_hcd 0000:00:1a.1: irq 21, io base 0x00001860
[ 3.383523] hub 2-0:1.0: USB hub found
[ 3.383649] hub 2-0:1.0: 2 ports detected
[ 3.384187] uhci_hcd 0000:00:1a.2: UHCI Host Controller
[ 3.384197] uhci_hcd 0000:00:1a.2: new USB bus registered, assigned bus number 3
[ 3.384207] uhci_hcd 0000:00:1a.2: detected 2 ports
[ 3.384245] uhci_hcd 0000:00:1a.2: irq 22, io base 0x00001880
[ 3.384679] hub 3-0:1.0: USB hub found
[ 3.384693] hub 3-0:1.0: 2 ports detected
[ 3.385046] uhci_hcd 0000:00:1d.0: UHCI Host Controller
[ 3.385056] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 4
[ 3.385067] uhci_hcd 0000:00:1d.0: detected 2 ports
[ 3.385104] uhci_hcd 0000:00:1d.0: irq 16, io base 0x000018a0
[ 3.385391] hub 4-0:1.0: USB hub found
[ 3.385405] hub 4-0:1.0: 2 ports detected
[ 3.386100] ehci-pci: EHCI PCI platform driver
[ 3.386149] uhci_hcd 0000:00:1d.1: UHCI Host Controller
[ 3.386159] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 5
[ 3.386169] uhci_hcd 0000:00:1d.1: detected 2 ports
[ 3.386210] uhci_hcd 0000:00:1d.1: irq 17, io base 0x000018c0
[ 3.386499] hub 5-0:1.0: USB hub found
[ 3.386512] hub 5-0:1.0: 2 ports detected
[ 3.387422] ehci-pci 0000:00:1a.7: EHCI Host Controller
[ 3.387433] ehci-pci 0000:00:1a.7: new USB bus registered, assigned bus number 6
[ 3.387454] ehci-pci 0000:00:1a.7: debug port 1
[ 3.390536] SCSI subsystem initialized
[ 3.391377] ehci-pci 0000:00:1a.7: cache line size of 64 is not supported
[ 3.391407] ehci-pci 0000:00:1a.7: irq 23, io mem 0xf0805c00
[ 3.393114] libata version 3.00 loaded.
[ 3.400023] ehci-pci 0000:00:1a.7: USB 2.0 started, EHCI 1.00
[ 3.400556] hub 6-0:1.0: USB hub found
[ 3.400572] hub 6-0:1.0: 6 ports detected
[ 3.420762] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input0
[ 3.423437] hub 1-0:1.0: USB hub found
[ 3.423452] hub 1-0:1.0: 2 ports detected
[ 3.446764] hub 2-0:1.0: USB hub found
[ 3.446781] hub 2-0:1.0: 2 ports detected
[ 3.470096] hub 3-0:1.0: USB hub found
[ 3.470113] hub 3-0:1.0: 2 ports detected
[ 3.470446] uhci_hcd 0000:00:1d.2: UHCI Host Controller
[ 3.470457] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 7
[ 3.470467] uhci_hcd 0000:00:1d.2: detected 2 ports
[ 3.470510] uhci_hcd 0000:00:1d.2: irq 18, io base 0x000018e0
[ 3.470855] hub 7-0:1.0: USB hub found
[ 3.470871] hub 7-0:1.0: 2 ports detected
[ 3.471114] ahci 0000:00:1f.2: version 3.0
[ 3.471277] ahci 0000:00:1f.2: irq 26 for MSI/MSI-X
[ 3.471324] ahci 0000:00:1f.2: SSS flag set, parallel bus scan disabled
[ 3.471354] ahci 0000:00:1f.2: AHCI 0001.0200 32 slots 4 ports 3 Gbps 0x1 impl SATA mode
[ 3.471359] ahci 0000:00:1f.2: flags: 64bit ncq sntf stag pm led clo pio slum part ccc
[ 3.472602] scsi host0: ahci
[ 3.472778] scsi host1: ahci
[ 3.472926] scsi host2: ahci
[ 3.475424] scsi host3: ahci
[ 3.475545] ata1: SATA max UDMA/133 abar m2048@0xf0805000 port 0xf0805100 irq 26
[ 3.475549] ata2: DUMMY
[ 3.475551] ata3: DUMMY
[ 3.475553] ata4: DUMMY
[ 3.476505] ehci-pci 0000:00:1d.7: EHCI Host Controller
[ 3.476517] ehci-pci 0000:00:1d.7: new USB bus registered, assigned bus number 8
[ 3.476540] ehci-pci 0000:00:1d.7: debug port 1
[ 3.480454] ehci-pci 0000:00:1d.7: cache line size of 64 is not supported
[ 3.480479] ehci-pci 0000:00:1d.7: irq 19, io mem 0xf0806000
[ 3.490041] ehci-pci 0000:00:1d.7: USB 2.0 started, EHCI 1.00
[ 3.490373] hub 8-0:1.0: USB hub found
[ 3.490387] hub 8-0:1.0: 6 ports detected
[ 3.513423] hub 4-0:1.0: USB hub found
[ 3.513436] hub 4-0:1.0: 2 ports detected
[ 3.536764] hub 5-0:1.0: USB hub found
[ 3.536781] hub 5-0:1.0: 2 ports detected
[ 3.560098] hub 7-0:1.0: USB hub found
[ 3.560115] hub 7-0:1.0: 2 ports detected
[ 3.793361] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 3.793627] ata1.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded
[ 3.793633] ata1.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out
[ 3.793664] ata1.00: ACPI cmd ef/5f:00:00:00:00:a0 (SET FEATURES) succeeded
[ 3.793670] ata1.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
[ 3.793788] ata1.00: ATA-8: TOSHIBA THNS128GG4BAAA-NonFDE, AGLA0203, max UDMA/100
[ 3.793792] ata1.00: 250069680 sectors, multi 16: LBA48
[ 3.794031] ata1.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded
[ 3.794035] ata1.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out
[ 3.794065] ata1.00: ACPI cmd ef/5f:00:00:00:00:a0 (SET FEATURES) succeeded
[ 3.794070] ata1.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
[ 3.794186] ata1.00: configured for UDMA/100
[ 3.794336] scsi 0:0:0:0: Direct-Access ATA TOSHIBA THNS128G 0203 PQ: 0 ANSI: 5
[ 3.826124] sd 0:0:0:0: [sda] 250069680 512-byte logical blocks: (128 GB/119 GiB)
[ 3.826227] sd 0:0:0:0: [sda] Write Protect is off
[ 3.826232] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 3.826278] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 3.827934] sda: sda1 sda2 sda3
[ 3.828454] sd 0:0:0:0: [sda] Attached SCSI disk
[ 3.863366] device-mapper: uevent: version 1.0.3
[ 3.863509] device-mapper: ioctl: 4.27.0-ioctl (2013-10-30) initialised: [email protected]
[ 13.087453] random: nonblocking pool is initialized
[ 17.023466] NET: Registered protocol family 38
[ 17.304211] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: (null)
[ 17.773165] thinkpad_ec: thinkpad_ec 0.41 loaded.
[ 17.776308] tp_smapi 0.41 loading...
[ 17.776557] tp_smapi successfully loaded (smapi_port=0xb2).
[ 17.785849] EXT4-fs (dm-0): re-mounted. Opts: data=ordered
[ 18.128026] Monitor-Mwait will be used to enter C-1 state
[ 18.128038] Monitor-Mwait will be used to enter C-2 state
[ 18.128045] Monitor-Mwait will be used to enter C-3 state
[ 18.128052] tsc: Marking TSC unstable due to TSC halts in idle
[ 18.128109] ACPI: acpi_idle registered with cpuidle
[ 18.128216] input: Lid Switch as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0D:00/input/input2
[ 18.128538] ACPI: Lid Switch [LID]
[ 18.128632] input: Sleep Button as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0E:00/input/input3
[ 18.128638] ACPI: Sleep Button [SLPB]
[ 18.128774] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input4
[ 18.128779] ACPI: Power Button [PWRF]
[ 18.133197] Switched to clocksource hpet
[ 18.157152] agpgart-intel 0000:00:00.0: Intel GM45 Chipset
[ 18.157193] agpgart-intel 0000:00:00.0: detected gtt size: 2097152K total, 262144K mappable
[ 18.158391] agpgart-intel 0000:00:00.0: detected 32768K stolen memory
[ 18.158864] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
[ 18.161295] thermal LNXTHERM:00: registered as thermal_zone0
[ 18.161300] ACPI: Thermal Zone [THM0] (49 C)
[ 18.163180] thermal LNXTHERM:01: registered as thermal_zone1
[ 18.163184] ACPI: Thermal Zone [THM1] (47 C)
[ 18.201123] systemd-journald[151]: Received request to flush runtime journal from PID 1
[ 18.211042] tpm_tis 00:05: 1.2 TPM (device-id 0x1020, rev-id 6)
[ 18.211049] tpm_tis 00:05: Intel iTPM workaround enabled
[ 18.214146] Non-volatile memory driver v1.3
[ 18.215056] ACPI: Battery Slot [BAT0] (battery present)
[ 18.216407] ACPI: AC Adapter [AC] (on-line)
[ 18.254681] [drm] Initialized drm 1.1.0 20060810
[ 18.486984] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
[ 18.488981] ACPI Warning: SystemIO range 0x0000000000001028-0x000000000000102f conflicts with OpRegion 0x0000000000001000-0x000000000000107f (\_SB_.PCI0.LPC_.PMIO) (20140724/utaddress-258)
[ 18.488992] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver
[ 18.488998] ACPI Warning: SystemIO range 0x00000000000011b0-0x00000000000011bf conflicts with OpRegion 0x0000000000001180-0x00000000000011ff (\_SB_.PCI0.LPC_.LPIO) (20140724/utaddress-258)
[ 18.489003] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver
[ 18.489006] ACPI Warning: SystemIO range 0x0000000000001180-0x00000000000011af conflicts with OpRegion 0x0000000000001180-0x00000000000011ff (\_SB_.PCI0.LPC_.LPIO) (20140724/utaddress-258)
[ 18.489011] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver
[ 18.489014] lpc_ich: Resource conflict(s) found affecting gpio_ich
[ 18.489532] wmi: Mapper loaded
[ 18.496450] i801_smbus 0000:00:1f.3: SMBus using PCI Interrupt
[ 18.528954] thinkpad_acpi: ThinkPad ACPI Extras v0.25
[ 18.528960] thinkpad_acpi: http://ibm-acpi.sf.net/
[ 18.528962] thinkpad_acpi: ThinkPad BIOS 6EET55WW (3.15 ), EC 6EHT11WW-1.05
[ 18.528965] thinkpad_acpi: Lenovo ThinkPad X301, model 27763JG
[ 18.562827] mei_me 0000:00:03.0: irq 27 for MSI/MSI-X
[ 18.576844] thinkpad_acpi: detected a 16-level brightness capable ThinkPad
[ 18.578163] thinkpad_acpi: radio switch found; radios are enabled
[ 18.578329] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
[ 18.578333] thinkpad_acpi: Disabling thinkpad-acpi brightness events by default...
[ 18.589581] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one
[ 18.589742] thinkpad_acpi: Console audio control enabled, mode: monitor (read only)
[ 18.593495] input: ThinkPad Extra Buttons as /devices/platform/thinkpad_acpi/input/input5
[ 18.602509] input: PC Speaker as /devices/platform/pcspkr/input/input6
[ 18.608125] cfg80211: Calling CRDA to update world regulatory domain
[ 18.608227] [drm] Memory usable by graphics device = 2048M
[ 18.608232] checking generic (d0000000 500000) vs hw (d0000000 10000000)
[ 18.608235] fb: switching to inteldrmfb from VESA VGA
[ 18.608267] Console: switching to colour dummy device 80x25
[ 18.608458] [drm] Replacing VGA console driver
[ 18.627881] Intel(R) Wireless WiFi driver for Linux, in-tree:
[ 18.627886] Copyright(c) 2003- 2014 Intel Corporation
[ 18.628049] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[ 18.628121] iwlwifi 0000:03:00.0: irq 28 for MSI/MSI-X
[ 18.633437] i915 0000:00:02.0: irq 29 for MSI/MSI-X
[ 18.633498] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 18.633501] [drm] Driver supports precise vblank timestamp query.
[ 18.633597] vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 18.643232] iwlwifi 0000:03:00.0: loaded firmware version 8.83.5.1 build 33692 op_mode iwldvm
[ 18.691553] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled
[ 18.691558] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS disabled
[ 18.691561] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[ 18.691565] iwlwifi 0000:03:00.0: Detected Intel(R) Ultimate N WiFi Link 5300 AGN, REV=0x24
[ 18.691646] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 18.728972] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: data=ordered
[ 18.767043] iTCO_vendor_support: vendor-support=0
[ 18.775548] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
[ 18.775618] iTCO_wdt: Found a ICH9M-E TCO device (Version=2, TCOBASE=0x1060)
[ 18.781996] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0)
[ 18.792476] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'
[ 18.822944] iwlwifi 0000:03:00.0 wls1: renamed from wlan0
[ 18.836659] fbcon: inteldrmfb (fb0) is primary device
[ 19.343552] Console: switching to colour frame buffer device 180x56
[ 19.352308] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 19.352310] i915 0000:00:02.0: registered panic notifier
[ 19.375020] ACPI: Video Device [VID] (multi-head: yes rom: no post: no)
[ 19.397558] acpi device:01: registered as cooling_device2
[ 19.398077] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input8
[ 19.398394] [drm] Initialized i915 1.6.0 20140725 for 0000:00:02.0 on minor 0
[ 19.398598] snd_hda_intel 0000:00:1b.0: irq 30 for MSI/MSI-X
[ 19.444984] sound hdaudioC0D0: CX20561 (Hermosa): BIOS auto-probing.
[ 19.445424] sound hdaudioC0D0: autoconfig: line_outs=1 (0x1a/0x0/0x0/0x0/0x0) type:speaker
[ 19.445428] sound hdaudioC0D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
[ 19.445432] sound hdaudioC0D0: hp_outs=2 (0x19/0x16/0x0/0x0/0x0)
[ 19.445435] sound hdaudioC0D0: mono: mono_out=0x0
[ 19.445438] sound hdaudioC0D0: dig-out=0x1c/0x0
[ 19.445440] sound hdaudioC0D0: inputs:
[ 19.445444] sound hdaudioC0D0: Mic=0x18
[ 19.445447] sound hdaudioC0D0: Internal Mic=0x1d
[ 19.445450] sound hdaudioC0D0: Dock Mic=0x17
[ 19.446528] sound hdaudioC0D0: Enable sync_write for stable communication
[ 19.460104] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/sound/card0/hdaudioC0D0/input9
[ 19.460484] input: HDA Intel Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input10
[ 19.460612] input: HDA Intel Dock Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input11
[ 19.460739] input: HDA Intel Dock Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12
[ 19.460861] input: HDA Intel Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input13
[ 19.507357] psmouse serio1: synaptics: Touchpad model: 1, fw: 7.2, id: 0x1a0b1, caps: 0xd047b3/0xb40000/0xa0000, board id: 71, fw id: 572156
[ 19.507368] psmouse serio1: synaptics: serio: Synaptics pass-through port at isa0060/serio1/input0
[ 19.552922] input: SynPS/2 Synaptics TouchPad as /devices/platform/i8042/serio1/input/input7
[ 19.553788] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 19.554188] iwlwifi 0000:03:00.0: Radio type=0x0-0x2-0x0
[ 19.559479] mousedev: PS/2 mouse device common for all mice
[ 19.687534] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 19.687940] iwlwifi 0000:03:00.0: Radio type=0x0-0x2-0x0
[ 19.715231] IPv6: ADDRCONF(NETDEV_UP): wls1: link is not ready
[ 20.522949] cfg80211: Calling CRDA to update world regulatory domain
[ 23.184174] wls1: authenticate with 34:31:c4:5f:07:d1
[ 23.190197] wls1: send auth to 34:31:c4:5f:07:d1 (try 1/3)
[ 23.193077] wls1: authenticated
[ 23.193382] wls1: associate with 34:31:c4:5f:07:d1 (try 1/3)
[ 23.201867] wls1: RX AssocResp from 34:31:c4:5f:07:d1 (capab=0x431 status=0 aid=4)
[ 23.213427] wls1: associated
[ 23.213484] IPv6: ADDRCONF(NETDEV_CHANGE): wls1: link becomes ready
[ 23.213555] cfg80211: Calling CRDA to update world regulatory domain
[ 24.474590] psmouse serio2: trackpoint: IBM TrackPoint firmware: 0x0e, buttons: 3/3
[ 24.727431] input: TPPS/2 IBM TrackPoint as /devices/platform/i8042/serio1/serio2/input/input14
[ 26.135183] fuse init (API version 7.23)
[ 325.938870] wls1: AP 34:31:c4:5f:07:d1 changed bandwidth, new config is 2432 MHz, width 1 (2432/0 MHz)
[ 1198.431306] perf interrupt took too long (2511 > 2495), lowering kernel.perf_event_max_sample_rate to 50100
[ 1284.185106] tun: Universal TUN/TAP device driver, 1.6
[ 1284.185111] tun: (C) 1999-2004 Max Krasnyansky <[email protected]>
[ 1284.215129] Bridge firewalling registered
[ 1284.229704] device tap0 entered promiscuous mode
[ 1284.241864] IPv6: ADDRCONF(NETDEV_UP): qemubr0: link is not ready
[ 2126.210933] wls1: AP 34:31:c4:5f:07:d1 changed bandwidth, new config is 2432 MHz, width 2 (2422/0 MHz)
[ 2426.034294] wls1: AP 34:31:c4:5f:07:d1 changed bandwidth, new config is 2432 MHz, width 1 (2432/0 MHz)
[ 2892.936374] kvm: zapping shadow pages for mmio generation wraparound
[ 2911.505834] kvm [958]: vcpu0 disabled perfctr wrmsr: 0xc1 data 0xffff
ip link / addr on host:
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: wls1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:21:6a:a9:49:ae brd ff:ff:ff:ff:ff:ff
inet 192.168.178.32/24 brd 192.168.178.255 scope global wls1
valid_lft forever preferred_lft forever
inet6 fe80::2176:234a:73c6:16a7/64 scope link
valid_lft forever preferred_lft forever
3: tap0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master qemubr0 state DOWN group default qlen 500
link/ether 7a:16:ef:9e:39:78 brd ff:ff:ff:ff:ff:ff
4: qemubr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 7a:16:ef:9e:39:78 brd ff:ff:ff:ff:ff:ff
# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: wls1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DORMANT group default qlen 1000
link/ether 00:21:6a:a9:49:ae brd ff:ff:ff:ff:ff:ff
3: tap0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master qemubr0 state DOWN mode DEFAULT group default qlen 500
link/ether 7a:16:ef:9e:39:78 brd ff:ff:ff:ff:ff:ff
4: qemubr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default
link/ether 7a:16:ef:9e:39:78 brd ff:ff:ff:ff:ff:ff
VM ip addr / link
http://oi58.tinypic.com/16kt11k.jpg
VM dmesg (extract), probably not helpful
http://oi59.tinypic.com/2i7l2qv.jpg
I must admit that my theoretical and practical knowledge on networking is quite limited, so this might be trivial. I'd be happy about any hints in the right direction. Thanks
-- mod edit: read the Forum Etiquette and only post thumbnails http://wiki.archlinux.org/index.php/For … s_and_Code and please don't post images of text [jwr] --
Last edited by AndyBrandi (2015-01-01 17:48:08)

Answer 1

You are scratching your right ear with the left hand, so to speak.
Let's say on the host, you have a bridge, br0, with an appropriate IP, serving as a gateway (created with your favorite network manager), and you'd like to start a VM whose virtual drive is arch-x86_64, then this is all you need to do:
$ qemu-system-x86_64 -enable-kvm -drive file=arch-x86_64,if=virtio -net nic,model=virtio -net bridge,br=br0
inside the VM you'll have eth0 (or whatever), and on the host -- tap0 plugged into the bridge. This is all courtesy of /usr/lib/qemu/qemu-bridge-helper which is a suid binary.
Last edited by Leonid.I (2015-01-03 23:24:41)