Re: [Xen-devel] Xen virtual IOMMU high level design doc V3

[Julien Grall <julien.grall@xxxxxxx>]

Hi Lan,

On 17/11/2016 09:36, Lan Tianyu wrote:

> 1) Definition of "struct xen_dmop_viommu_op" as new hypercall parameter.
>
> struct xen_dmop_viommu_op {
>     u32 cmd;
>     u32 domid;
>     u32 viommu_id;
>     union {
>         struct {
>             u32 capabilities;
>         } query_capabilities;
>         struct {
>             /* IN parameters. */
>             u32 capabilities;
>             u64 base_address;
>             struct {
>                 u32 size;
>                 XEN_GUEST_HANDLE_64(uint32) dev_list;
>             } dev_scope;
>             /* Out parameters. */
>             u32 viommu_id;
>         } create_iommu;
>             struct {
>             /* IN parameters. */
>             u32 vsbdf;
I only gave a quick look through this design document. The new 
hypercalls looks arch/device agnostic except this part.
Having a virtual IOMMU on Xen ARM is something we might consider in the 
future.
In the case of ARM, a device can either be a PCI device or integrated 
device. The latter does not have a sbdf. The IOMMU will usually be 
configured with a stream ID (SID) that can be deduced from the sbdf and 
hardcoded for integrated device.
So I would rather not tie the interface to PCI and use a more generic 
name for this field. Maybe vdevid, which then can be architecture specific.
Regards,

--
Julien Grall

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