Re: [Qemu-devel] [Qemu-arm] [RFC v3 0/8] VIRTIO-IOMMU device

[Linu Cherian <linuc.decode@gmail.com>]

Hi Eric,

On Tue Aug 01, 2017 at 11:33:06AM +0200, Eric Auger wrote:
> This series implements the virtio-iommu device.
> 
> This v3 mostly is a rebase on top of v2.10-rc0 that uses
> IOMMUMmeoryRegion plus some small fixes.
> 
> This is a proof of concept based on the virtio-iommu specification
> written by Jean-Philippe Brucker [1].
> 
> The device gets instantiated using the "-device virtio-iommu-device"
> option. It currently works with ARM virt machine only, as the machine
> must handle the dt binding between the virtio-mmio "iommu" node and
> the PCI host bridge node.
> 
> ACPI booting is not yet supported.
> 
> Best Regards
> 
> Eric
> 
> This series can be found at:
> https://github.com/eauger/qemu/tree/v2.10.0-rc0-virtio-iommu-rfcv3
> 
> References:
> [1] [RFC 0/3] virtio-iommu: a paravirtualized IOMMU,
> [2] [RFC PATCH linux] iommu: Add virtio-iommu driver
> [3] [RFC PATCH kvmtool 00/15] Add virtio-iommu
> 
> Testing:
> - >= 4.12 guest kernel + virtio-iommu driver [2]
> - guest using a virtio-net-pci device:
>   ,vhost=off,iommu_platform,disable-modern=off,disable-legacy=on

Was trying to test this out and facing issues.
Guest and Host Kernel - git://linux-arm.org/linux-jpb.git, Branch virtio-iommu/v0.4
Qemu - As mentioned above.

Relevant Qemu command - -device virtio-iommu-device \
-netdev type=tap,id=eth0,ifname=tap0,vhost=off,script=no,downscript=no \
-device virtio-net-pci,netdev=eth0,iommu_platform,disable-modern=off,disable-legacy=on

Issue:
Though guest boots with virtio-iommu device probe succuessful,
virtio net device probe gets failed.

928763] virtio_iommu virtio0: aperture: 0x0-0xffffffffffffffff
[    0.933145] virtio_iommu virtio0: page mask: 0xfffffffffffff000
[    0.937333] virtio_iommu virtio0: probe successful

...

virtio_net: probe of virtio2 failed with error -12"


Even before this failure, i did saw couple of repeated warnings.

73085] ------------[ cut here ]------------
[    2.576330] WARNING: CPU: 0 PID: 49 at drivers/iommu/dma-iommu.c:904 iommu_dma_map_msi_msg+0x1dc/0x1f4
[    2.582963] Modules linked in:
[    2.585210] CPU: 0 PID: 49 Comm: kworker/0:1 Tainted: G        W       4.13.0-rc1-gd1949df-dirty #14
[    2.591733] Hardware name: linux,dummy-virt (DT)
[    2.595062] Workqueue: events deferred_probe_work_func
[    2.598777] task: ffff80003e0c0d80 task.stack: ffff80003e104000
[    2.603036] PC is at iommu_dma_map_msi_msg+0x1dc/0x1f4
[    2.606745] LR is at iommu_dma_map_msi_msg+0x1dc/0x1f4
....
snip
....
   2.735988] [<ffff000008658b18>] iommu_dma_map_msi_msg+0x1dc/0x1f4
[    2.740429] [<ffff00000858846c>] its_irq_compose_msi_msg+0x5c/0x68
[    2.744869] [<ffff00000811e3f4>] irq_chip_compose_msi_msg+0x5c/0x74
[    2.749378] [<ffff000008123d04>] msi_domain_activate+0x24/0x4c
[    2.753577] [<ffff0000081202fc>] __irq_domain_activate_irq+0x48/0x54
[    2.758151] [<ffff00000812231c>] irq_domain_activate_irq+0x2c/0x48
[    2.762593] [<ffff0000081242cc>] msi_domain_alloc_irqs+0x150/0x214
[    2.767038] [<ffff0000085c4edc>] pci_msi_setup_msi_irqs+0x5c/0x68
[    2.771560] [<ffff0000085c5544>] __pci_enable_msix+0x41c/0x4c0
[    2.775778] [<ffff0000085c5d1c>] pci_alloc_irq_vectors_affinity+0xac/0x160
[    2.780709] [<ffff0000085ff6e4>] vp_find_vqs_msix+0x148/0x440
[    2.784848] [<ffff0000085ffa8c>] vp_find_vqs+0xb0/0x1b8
[    2.788624] [<ffff0000085fe798>] vp_modern_find_vqs+0x50/0xa8
[    2.792768] [<ffff000008723454>] init_vqs+0x394/0x600
[    2.796417] [<ffff000008723b50>] virtnet_probe+0x3c4/0x77c
[    2.800370] [<ffff0000085fa738>] virtio_dev_probe+0x198/0x230
[    2.804507] [<ffff00000866aa38>] driver_probe_device+0x298/0x440
[    2.808827] [<ffff00000866ae00>] __device_attach_driver+0x9c/0x140
[    2.813269] [<ffff0000086686c8>] bus_for_each_drv+0x68/0xa8
[    2.817283] [<ffff00000866a5e4>] __device_attach+0xcc/0x15c
[    2.821299] [<ffff00000866aec8>] device_initial_probe+0x24/0x30
[    2.825558] [<ffff00000866994c>] bus_probe_device+0x9c/0xa4
[    2.829574] [<ffff000008667328>] device_add+0x378/0x5c8
[    2.833344] [<ffff0000086675a0>] device_register+0x28/0x34
[    2.837302] [<ffff0000085fa22c>] register_virtio_device+0xbc/0x10c
[    2.841747] [<ffff0000085ff2cc>] virtio_pci_probe+0xdc/0x14c
[    2.845822] [<ffff0000085abf8c>] local_pci_probe+0x50/0xb4
[    2.849784] [<ffff0000085acd8c>] pci_device_probe+0x168/0x178
[    2.853926] [<ffff00000866aa38>] driver_probe_device+0x298/0x440
[    2.858243] [<ffff00000866ae00>] __device_attach_driver+0x9c/0x140
[    2.862681] [<ffff0000086686c8>] bus_for_each_drv+0x68/0xa8
[    2.866692] [<ffff00000866a5e4>] __device_attach+0xcc/0x15c
[    2.870707] [<ffff00000866aec8>] device_initial_probe+0x24/0x30
[    2.874966] [<ffff00000866994c>] bus_probe_device+0x9c/0xa4
[    2.878982] [<ffff000008669f68>] deferred_probe_work_func+0xa0/0xec
[    2.883487] [<ffff0000080db09c>] process_one_work+0x160/0x384
[    2.887623] [<ffff0000080db4b4>] worker_thread+0x1f4/0x3d8
[    2.891577] [<ffff0000080e1b48>] kthread+0x10c/0x138
[    2.895165] [<ffff0000080833b0>] ret_from_fork+0x10/0x20


Am i missing something ?


> 
> History:
> v2 -> v3:
> - rebase on top of 2.10-rc0 and especially
>   [PATCH qemu v9 0/2] memory/iommu: QOM'fy IOMMU MemoryRegion
> - add mutex init
> - fix as->mappings deletion using g_tree_ref/unref
> - when a dev is attached whereas it is already attached to
>   another address space, first detach it
> - fix some error values
> - page_sizes = TARGET_PAGE_MASK;
> - I haven't changed the unmap() semantics yet, waiting for the
>   next virtio-iommu spec revision.
> 
> v1 -> v2:
> - fix redifinition of viommu_as typedef
> 
> 
> Eric Auger (8):
>   update-linux-headers: import virtio_iommu.h
>   linux-headers: Update for virtio-iommu
>   virtio_iommu: add skeleton
>   virtio-iommu: Decode the command payload
>   virtio_iommu: Add the iommu regions
>   virtio-iommu: Implement the translation and commands
>   hw/arm/virt: Add 2.10 machine type
>   hw/arm/virt: Add virtio-iommu the virt board
> 
>  hw/arm/virt.c                                 | 116 ++++-
>  hw/virtio/Makefile.objs                       |   1 +
>  hw/virtio/trace-events                        |  14 +
>  hw/virtio/virtio-iommu.c                      | 670 ++++++++++++++++++++++++++
>  include/hw/arm/virt.h                         |   5 +
>  include/hw/virtio/virtio-iommu.h              |  61 +++
>  include/standard-headers/linux/virtio_ids.h   |   1 +
>  include/standard-headers/linux/virtio_iommu.h | 142 ++++++
>  linux-headers/linux/virtio_iommu.h            |   1 +
>  scripts/update-linux-headers.sh               |   3 +
>  10 files changed, 1005 insertions(+), 9 deletions(-)
>  create mode 100644 hw/virtio/virtio-iommu.c
>  create mode 100644 include/hw/virtio/virtio-iommu.h
>  create mode 100644 include/standard-headers/linux/virtio_iommu.h
>  create mode 100644 linux-headers/linux/virtio_iommu.h
> 
> -- 
> 2.5.5
> 
> 

-- 
Linu cherian