Re: [Qemu-devel] [PATCH 4/7] vfio: Record host IOMMU's available IO page sizes

[Alex Williamson <alex.williamson@redhat.com>]

On Thu, 2015-09-24 at 14:33 +1000, David Gibson wrote:
> Depending on the host IOMMU type we determine and record the available page
> sizes for IOMMU translation.  We'll need this for other validation in
> future patches.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hw/vfio/common.c              | 13 +++++++++++++
>  include/hw/vfio/vfio-common.h |  1 +
>  2 files changed, 14 insertions(+)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index f90cc75..db8dff3 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -677,6 +677,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
>      if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
>          ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
>          bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);
> +        struct vfio_iommu_type1_info info;
>  
>          ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
>          if (ret) {
> @@ -702,6 +703,15 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
>           */
>          container->min_iova = 0;
>          container->max_iova = (hwaddr)-1;
> +
> +        /* Assume just 4K IOVA page size */
> +        container->iova_pgsizes = 0x1000;
> +        info.argsz = sizeof(info);
> +        ret = ioctl(fd, VFIO_IOMMU_GET_INFO, &info);
> +        /* Ignore errors */
> +        if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) {
> +            container->iova_pgsizes = info.iova_pgsizes;
> +        }
>      } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
>          struct vfio_iommu_spapr_tce_info info;
>  
> @@ -744,6 +754,9 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
>          }
>          container->min_iova = info.dma32_window_start;
>          container->max_iova = container->min_iova + info.dma32_window_size - 1;
> +
> +        /* Assume just 4K IOVA pages for now */


Ironically, no FIXME ;)

> +        container->iova_pgsizes = 0x1000;
>      } else {
>          error_report("vfio: No available IOMMU models");
>          ret = -EINVAL;
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 859dbec..b8a76e1 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -71,6 +71,7 @@ typedef struct VFIOContainer {
>       * that in future
>       */
>      hwaddr min_iova, max_iova;
> +    uint64_t iova_pgsizes;
>      QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
>      QLIST_HEAD(, VFIOGroup) group_list;
>      QLIST_ENTRY(VFIOContainer) next;