On Mon, 14 Mar 2022 15:44:34 -0400
Matthew Rosato <mjrosato@xxxxxxxxxxxxx> wrote:
> s390x will introduce a new IOMMU domain type where the mappings are
> managed by KVM rather than in response to userspace mapping ioctls. Allow
> for specifying this type on the VFIO_SET_IOMMU ioctl and triggering the
> appropriate iommu interface for overriding the default domain.
>
> Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> ---
> drivers/vfio/vfio_iommu_type1.c | 12 +++++++++++-
> include/uapi/linux/vfio.h | 6 ++++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 9394aa9444c1..0bec97077d61 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -77,6 +77,7 @@ struct vfio_iommu {
> bool nesting;
> bool dirty_page_tracking;
> bool container_open;
> + bool kvm;
> struct list_head emulated_iommu_groups;
> };
>
> @@ -2203,7 +2204,12 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> goto out_free_group;
>
> ret = -EIO;
> - domain->domain = iommu_domain_alloc(bus);
> +
> + if (iommu->kvm)
> + domain->domain = iommu_domain_alloc_type(bus, IOMMU_DOMAIN_KVM);
> + else
> + domain->domain = iommu_domain_alloc(bus);
> +
> if (!domain->domain)
> goto out_free_domain;
>
> @@ -2552,6 +2558,9 @@ static void *vfio_iommu_type1_open(unsigned long arg)
> case VFIO_TYPE1v2_IOMMU:
> iommu->v2 = true;
> break;
> + case VFIO_KVM_IOMMU:
> + iommu->kvm = true;
> + break;
> default:
> kfree(iommu);
> return ERR_PTR(-EINVAL);
> @@ -2637,6 +2646,7 @@ static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
> case VFIO_TYPE1_NESTING_IOMMU:
> case VFIO_UNMAP_ALL:
> case VFIO_UPDATE_VADDR:
> + case VFIO_KVM_IOMMU:
> return 1;
> case VFIO_DMA_CC_IOMMU:
> if (!iommu)
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index ef33ea002b0b..666edb6957ac 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -52,6 +52,12 @@
> /* Supports the vaddr flag for DMA map and unmap */
> #define VFIO_UPDATE_VADDR 10
>
> +/*
> + * The KVM_IOMMU type implies that the hypervisor will control the mappings
> + * rather than userspace
> + */
> +#define VFIO_KVM_IOMMU 11
Then why is this hosted in the type1 code that exposes a wide variety
of userspace interfaces? Thanks,
Alex
