lkml.org 
[lkml]   [2013]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH] iommu/exynos: add devices attached to the System MMU to an IOMMU group
Date


> -----Original Message-----
> From: linux-samsung-soc-owner@vger.kernel.org [mailto:linux-samsung-soc-
> owner@vger.kernel.org] On Behalf Of Antonios Motakis
> Sent: Tuesday, July 23, 2013 7:02 PM
> To: linux-arm-kernel@lists.infradead.org;
iommu@lists.linux-foundation.org;
> linux-samsung-soc@vger.kernel.org
> Cc: kvmarm@lists.cs.columbia.edu; Antonios Motakis; Cho KyongHo; Joerg
> Roedel; Sachin Kamat; Jiri Kosina; Wei Yongjun; open list
> Subject: [PATCH] iommu/exynos: add devices attached to the System MMU to
> an IOMMU group
>
> IOMMU groups are expected by certain users of the IOMMU API,
> e.g. VFIO. Since each device is behind its own System MMU, we
> can allocate a new IOMMU group for each device.
>
> This patch depends on Cho KyongHo's patch series titled "[PATCH v7 00/12]
> iommu/exynos: Fixes and Enhancements of System MMU driver with DT",
> applied on a Linux 3.10.1 kernel. It has been tested on the Arndale board.
>
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> ---
> drivers/iommu/exynos-iommu.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index 51d43bb..9f39eaa 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -1134,6 +1134,28 @@ static phys_addr_t exynos_iommu_iova_to_phys(struct
> iommu_domain *domain,
> return phys;
> }
>
> +static int exynos_iommu_add_device(struct device *dev)
> +{
> + struct iommu_group *group;
> + int ret;
> +
> + group = iommu_group_alloc();

Is that correct? I don't see why you allocate a group object every time
add_device callback is called. That doesn't have any meaning we have to use
iommu group feature. I think the implementation should be one more devices
per a group. So I guess a given device object should be wrapped by higher
device object than the given device object. For a good example, you can
refer to intel-iommu.c file.

Thanks,
Inki Dae

> + if (IS_ERR(group)) {
> + dev_err(dev, "Failed to allocate IOMMU group\n");
> + return PTR_ERR(group);
> + }
> +
> + ret = iommu_group_add_device(group, dev);
> + iommu_group_put(group);
> +
> + return ret;
> +}
> +
> +static void exynos_iommu_remove_device(struct device *dev)
> +{
> + iommu_group_remove_device(dev);
> +}
> +
> static struct iommu_ops exynos_iommu_ops = {
> .domain_init = &exynos_iommu_domain_init,
> .domain_destroy = &exynos_iommu_domain_destroy,
> @@ -1142,6 +1164,8 @@ static struct iommu_ops exynos_iommu_ops = {
> .map = &exynos_iommu_map,
> .unmap = &exynos_iommu_unmap,
> .iova_to_phys = &exynos_iommu_iova_to_phys,
> + .add_device = exynos_iommu_add_device,
> + .remove_device = exynos_iommu_remove_device,
> .pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,
> };
>
> --
> 1.8.1.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-
> soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html



\
 
 \ /
  Last update: 2013-07-23 13:21    [W:0.070 / U:0.548 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site