Re: Status of pci passthrough work?

[Thomas Fjellstrom <tfjellstrom@shaw.ca>]

On Saturday 27 September 2008, Jan C. Bernauer wrote:
> Hi,
>
>  I have about the same problem, so excuse me for hijacking this thread.
>
> My hardware consists of a 780g/SB700 Mainboard and a 4850e AMD CPU, and
> I'm interested in forwarding a DVB-C tuner card to the guest. Maybe
> some NICs later.
>
> I tried and 'sort of' got it working with Amit's kernel and userspace
> tools.
> First thing:
> The dvb-c card has an interesting memory mapping, as reported by
> lspci -v:
>         Memory at cfdff000 (32-bit, non-prefetchable) [size=512]
>
> Size 512 doesn't fly with a check in kvm_main.c:
> if (mem->memory_size & (PAGE_SIZE - 1))
>                 goto out;
>
> So I patched the userspace utilities to use 4096 instead.
>
> With that patch, the guest saw the card, the driver got loaded,
> and channel tuning works, but I get some i2c timeouts on the
> guest side, and the host side has errors like:
>
> ------------[ cut here ]------------
> Sep 22 02:28:54 [kernel] WARNING: at kernel/irq/manage.c:180
> enable_irq+0x3a/0x55()
> Sep 22 02:28:54 [kernel] Unbalanced enable for IRQ 20
> Sep 22 02:28:54 [kernel] Modules linked in: sha256_generic cbc dm_crypt
> crypto_blkcipher kvm_amd kvm bridge stp llc stv0297 budget_core dvb_core
> saa7146 ttpci_eepr\
> om ir_common k8temp i2c_core dm_snapshot dm_mirror dm_log scsi_wait_scan
> [last unloaded: budget_ci]
> Sep 22 02:28:54 [kernel] Pid: 5283, comm: qemu-system-x86 Tainted: G
>     W 2.6.27-rc5-11874-g19561b6 #11
> Sep 22 02:28:54 [kernel] Call Trace:
> Sep 22 02:28:54 [kernel]  [<ffffffff80238b04>] warn_slowpath+0xb4/0xdc
> Sep 22 02:28:54 [kernel]  [<ffffffff8026b099>]
> __alloc_pages_internal+0xde/0x419
> Sep 22 02:28:54 [kernel]  [<ffffffff802758d0>] get_user_pages+0x401/0x4ae
> Sep 22 02:28:54 [kernel]  [<ffffffff80349269>] __next_cpu+0x19/0x26
> Sep 22 02:28:54 [kernel]  [<ffffffff80230ce2>]
> find_busiest_group+0x315/0x7c3
> Sep 22 02:28:54 [kernel]  [<ffffffffa005de31>] gfn_to_hva+0x9/0x5d [kvm]
>                 - Last output repeated twice -
> Sep 22 02:28:54 [kernel]  [<ffffffffa005e01b>]
> kvm_read_guest_page+0x34/0x46 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa005e06c>] kvm_read_guest+0x3f/0x7c
> [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa0068bfe>]
> paging64_walk_addr+0xe0/0x2c1 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffff80260d59>] enable_irq+0x3a/0x55
> Sep 22 02:28:54 [kernel]  [<ffffffffa006df50>]
> kvm_notify_acked_irq+0x17/0x30 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa00701c5>]
> kvm_ioapic_update_eoi+0x2f/0x6e [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa006f6da>]
> apic_mmio_write+0x24a/0x546 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa006498d>]
> emulator_write_emulated_onepage+0xa1/0xf3 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffff802206f8>]
> paravirt_patch_call+0x13/0x2b Sep 22 02:28:54 [kernel] 
> [<ffffffffa006c93e>]
> x86_emulate_insn+0x366a/0x41de [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffff802206fa>]
> paravirt_patch_call+0x15/0x2b Sep 22 02:28:54 [kernel] 
> [<ffffffffa005f90b>]
> kvm_get_cs_db_l_bits+0x22/0x3a [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa006167d>]
> emulate_instruction+0x198/0x25c [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa0067dfe>]
> kvm_mmu_page_fault+0x46/0x83 [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa00636a9>]
> kvm_arch_vcpu_ioctl_run+0x456/0x65c [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffff8024d605>] hrtimer_start+0x111/0x133
> Sep 22 02:28:54 [kernel]  [<ffffffffa005d451>] kvm_vcpu_ioctl+0xe0/0x459
> [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffffa005ee43>] kvm_vm_ioctl+0x203/0x21b
> [kvm]
> Sep 22 02:28:54 [kernel]  [<ffffffff802353b6>] finish_task_switch+0x2b/0xc4
> Sep 22 02:28:54 [kernel]  [<ffffffff8029e3b5>] vfs_ioctl+0x21/0x6c
> Sep 22 02:28:54 [kernel]  [<ffffffff8029e627>] do_vfs_ioctl+0x227/0x23d
> Sep 22 02:28:54 [kernel]  [<ffffffff8029e67a>] sys_ioctl+0x3d/0x5f
> Sep 22 02:28:54 [kernel]  [<ffffffff8020b45a>]
> system_call_fastpath+0x16/0x1b
> Sep 22 02:28:54 [kernel] ---[ end trace 7b8b990423985ddf ]---
> Sep 22 02:28:54 [kernel] ------------[ cut here ]------------
>
>
> Xen works with that card, but Xen has other problems, and kvm is much
> nicer :) So if you need a guinea pig with basic debugging knowledge, I'm
> your man.

How did you manage to pull together those patches? They all seem so old, and 
won't likely apply cleanly to git head :(

> Best regards,
> Jan C. Bernauer
>

-- 
Thomas Fjellstrom
tfjellstrom@shaw.ca