Re: [PATCH v5 0/5] VIRTIO-IOMMU probe request support and MSI bypass on ARM

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 24, 2020 at 03:26:20PM +0200, Eric Auger wrote:
> By default the virtio-iommu translates MSI transactions. This
> behavior is inherited from ARM SMMU. However the virt machine
> code knows where the MSI doorbells are, so we can easily
> declare those regions as VIRTIO_IOMMU_RESV_MEM_T_MSI. With that
> setting the guest iommu subsystem will not need to map MSIs.
> This setup will simplify the VFIO integration.
> 
> In this series, the ITS or GICV2M doorbells are declared as
> HW MSI regions to be bypassed by the VIRTIO-IOMMU.
> 
> This also paves the way to the x86 integration where the MSI
> region, [0xFEE00000,0xFEEFFFFF], will be exposed by the q35
> machine.  However this will be handled in a separate series
> when not-DT support gets resolved.
> 
> Best Regards
> 
> Eric


Virtio bits look OK:

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Who's merging this? ARM tree?

> This series can be found at:
> https://github.com/eauger/qemu/tree/v5.0.0-virtio-iommu-msi-bypass-v5
> 
> History:
> 
> v4 -> v5:
> - Take into account some additional comments from Markus:
>   - reserved region type becomes an unsigned + some comment/desc
>     rewording
>   - assert if the type is not RESERVED or MSI
> 
> v3 -> v4:
> - collected Jean and markus's R-bs
> - tool into account all Markus' comments in [1/5] (except removal of
>   goto)
> - use ':' as delimitor instead of commas
> - add example in 4/5 commit message as suggested by Markus
> 
> v2 -> v3:
> - Introduce VIRT_MSI_CTRL_NONE in VirtMSIControllerType
> - do not fill the remainder of the probe buffer
> 
> v1 -> v2:
> - check which MSI controller is in use and advertise the
>   corresponding MSI doorbell
> - managed for both ITS and GICv2M
> - various fixes spotted by Peter and Jean-Philippe, see
>   individual logs
> 
> v1: Most of those patches were respinned from
>   [PATCH for-5.0 v11 00/20] VIRTIO-IOMMU device
>   except the last one which is new
> 
> 
> Eric Auger (5):
>   qdev: Introduce DEFINE_PROP_RESERVED_REGION
>   virtio-iommu: Implement RESV_MEM probe request
>   virtio-iommu: Handle reserved regions in the translation process
>   virtio-iommu-pci: Add array of Interval properties
>   hw/arm/virt: Let the virtio-iommu bypass MSIs
> 
>  include/exec/memory.h            |   6 ++
>  include/hw/arm/virt.h            |   7 ++
>  include/hw/qdev-properties.h     |   3 +
>  include/hw/virtio/virtio-iommu.h |   2 +
>  include/qemu/typedefs.h          |   1 +
>  hw/arm/virt.c                    |  18 +++++
>  hw/core/qdev-properties.c        |  89 ++++++++++++++++++++++++
>  hw/virtio/virtio-iommu-pci.c     |   3 +
>  hw/virtio/virtio-iommu.c         | 112 +++++++++++++++++++++++++++++--
>  hw/virtio/trace-events           |   1 +
>  10 files changed, 238 insertions(+), 4 deletions(-)
> 
> -- 
> 2.20.1