WARNING with device passthrough and MSI interrupts

WARNING with device passthrough and MSI interrupts

[Joerg Roedel]

Hi,

passing a device through to a guest I sometimes get the following WARN
message on the host:

Dec  8 12:28:52 astat kernel: [  248.472109] WARNING: at kernel/irq/manage.c:225 enable_irq+0x6b/0x90()
Dec  8 12:28:52 astat kernel: [  248.472114] Unbalanced enable for IRQ 488
Dec  8 12:28:52 astat kernel: [  248.472118] Modules linked in: kvm_amd kvm af_packet radeon drm rfcomm sco bridge stp bnep l2cap bluetooth ppdev ipv6 powernow_k8 cpufreq_stats cpufreq_powersave cpufreq_conservative cpufreq_ondemand freq_table cpufreq_userspace video output rfkill input_polldev sbs sbshc battery iptable_filter ip_tables x_tables ac parport_pc lp parport psmouse serio_raw pcspkr i2c_piix4 i2c_core shpchp pci_hotplug container button evdev ext3 jbd mbcache usbhid hid sg sd_mod atiixp pata_acpi ata_generic ehci_hcd pata_atiixp ahci ohci_hcd bnx2 libata scsi_mod usbcore thermal processor fan thermal_sys fuse
Dec  8 12:28:52 astat kernel: [  248.472205] Pid: 5520, comm: qemu-system-x86 Tainted: G        W  2.6.28-rc7 #3
Dec  8 12:28:52 astat kernel: [  248.472210] Call Trace:
Dec  8 12:28:52 astat kernel: [  248.472224]  [<ffffffff8024124d>] warn_slowpath+0xcd/0x110
Dec  8 12:28:52 astat kernel: [  248.472235]  [<ffffffff8035cfd1>] elv_insert+0x141/0x300
Dec  8 12:28:52 astat kernel: [  248.472243]  [<ffffffff8035d9b3>] drive_stat_acct+0xc3/0xf0
Dec  8 12:28:52 astat kernel: [  248.472250]  [<ffffffff8035fe19>] __make_request+0xf9/0x4d0
Dec  8 12:28:52 astat kernel: [  248.472256]  [<ffffffff802355e8>] enqueue_task_fair+0x188/0x1e0
Dec  8 12:28:52 astat kernel: [  248.472290]  [<ffffffffa0351319>] gfn_to_hva+0x9/0x70 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472318]  [<ffffffffa0351621>] kvm_read_guest_page+0x61/0x70 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472343]  [<ffffffffa0351319>] gfn_to_hva+0x9/0x70 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472367]  [<ffffffffa0351621>] kvm_read_guest_page+0x61/0x70 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472390]  [<ffffffffa0351678>] kvm_read_guest+0x48/0x80 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472415]  [<ffffffffa0361a1c>] paging64_walk_addr+0x17c/0x330 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472422]  [<ffffffff8028983b>] enable_irq+0x6b/0x90
Dec  8 12:28:52 astat kernel: [  248.472447]  [<ffffffffa0354359>] kvm_notify_acked_irq+0x39/0x60 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472471]  [<ffffffffa0353eb2>] kvm_ioapic_update_eoi+0x42/0x90 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472495]  [<ffffffffa036a4eb>] apic_mmio_write+0x50b/0x6c0 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472505]  [<ffffffff8021ef25>] do_suspend_lowlevel+0x65/0x130
Dec  8 12:28:52 astat kernel: [  248.472529]  [<ffffffffa035b30b>] emulator_write_emulated_onepage+0x9b/0x120 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472556]  [<ffffffffa0362f03>] x86_emulate_insn+0x423/0x4a40 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472583]  [<ffffffffa0367872>] x86_decode_insn+0x352/0xed0 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472607]  [<ffffffffa03550d9>] kvm_get_cs_db_l_bits+0x29/0x50 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472633]  [<ffffffffa03575a7>] emulate_instruction+0x127/0x330 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472657]  [<ffffffffa03608cc>] kvm_mmu_page_fault+0x5c/0xa0 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472681]  [<ffffffffa0359929>] kvm_arch_vcpu_ioctl_run+0x299/0x850 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472705]  [<ffffffffa03507cb>] kvm_vcpu_ioctl+0x2fb/0x5b0 [kvm]
Dec  8 12:28:52 astat kernel: [  248.472714]  [<ffffffff802d4b2f>] vfs_ioctl+0x2f/0xb0
Dec  8 12:28:52 astat kernel: [  248.472721]  [<ffffffff802d4c2c>] do_vfs_ioctl+0x7c/0x480
Dec  8 12:28:52 astat kernel: [  248.472728]  [<ffffffff80266754>] sys_futex+0xc4/0x170
Dec  8 12:28:52 astat kernel: [  248.472735]  [<ffffffff802d50d1>] sys_ioctl+0xa1/0xb0
Dec  8 12:28:52 astat kernel: [  248.472741]  [<ffffffff8020c30b>] system_call_fastpath+0x16/0x1b
Dec  8 12:28:52 astat kernel: [  248.472746] ---[ end trace 0f717136b7f1724f ]---

IRQ 488 is assigned to the device passed through to the guest.

Joerg
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