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Date: Wed, 6 Dec 2017 16:15:59 +0000
From: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
To: "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
"eric.auger@...hat.com" <eric.auger@...hat.com>,
"pmorel@...ux.vnet.ibm.com" <pmorel@...ux.vnet.ibm.com>
CC: "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linuxarm <linuxarm@...wei.com>
Subject: RE: [RFC] vfio/type1: Add IOVA_RANGE capability support
Hi Pierre,
> -----Original Message-----
> From: Shameerali Kolothum Thodi
> Sent: Wednesday, December 06, 2017 4:08 PM
> To: alex.williamson@...hat.com; eric.auger@...hat.com;
> pmorel@...ux.vnet.ibm.com
> Cc: kvm@...r.kernel.org; linux-kernel@...r.kernel.org; Linuxarm
> <linuxarm@...wei.com>; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@...wei.com>
> Subject: [RFC] vfio/type1: Add IOVA_RANGE capability support
>
> This patch allows the user-space to retrieve the supported
> IOVA range(s), excluding any reserved regions. The implementation
> is based on capability chains, added to the VFIO_IOMMU_GET_INFO ioctl.
>
> This is following the discussions here[1] and is based on the RFC patch[2].
>
> ToDo:
> - This currently derives the default supported iova range from the first
> iommu domain. This needs to be changed to go through the domain_list
> instead.
> - Sync with Pierre's patch[3].
Thanks to Eric[1], came to know that you have posted a patch to retrieve the
iommu aperture info. This RFC does a similar thing but try to take care of
any reserved regions and adds to the capability chain.
Please take a look and if there is a possibility to sync up your next revision
and this, please let me know.
Thanks,
Shameer
1. https://patchwork.kernel.org/patch/10056967/
> 1.https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg03651.html
> 2.https://lists.linuxfoundation.org/pipermail/iommu/2016-
> November/019002.html
> 3.https://patchwork.kernel.org/patch/10084655/
>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 172
> +++++++++++++++++++++++++++++++++++++++-
> include/uapi/linux/vfio.h | 13 +++
> 2 files changed, 184 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index e30e29a..72ca78a 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -28,6 +28,7 @@
> #include <linux/device.h>
> #include <linux/fs.h>
> #include <linux/iommu.h>
> +#include <linux/list_sort.h>
> #include <linux/module.h>
> #include <linux/mm.h>
> #include <linux/rbtree.h>
> @@ -92,6 +93,12 @@ struct vfio_group {
> struct list_head next;
> };
>
> +struct vfio_iommu_iova {
> + struct list_head list;
> + phys_addr_t start;
> + phys_addr_t end;
> +};
> +
> /*
> * Guest RAM pinning working set or DMA target
> */
> @@ -1537,6 +1544,144 @@ static int vfio_domains_have_iommu_cache(struct
> vfio_iommu *iommu)
> return ret;
> }
>
> +static int vfio_add_iova_cap(struct vfio_info_cap *caps, u64 start, u64 end)
> +{
> + struct vfio_iommu_type1_info_cap_iova_range *cap;
> + struct vfio_info_cap_header *header;
> +
> + header = vfio_info_cap_add(caps, sizeof(*cap),
> + VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE, 1);
> + if (IS_ERR(header))
> + return PTR_ERR(header);
> +
> + cap = container_of(header,
> + struct vfio_iommu_type1_info_cap_iova_range,
> + header);
> +
> + cap->start = start;
> + cap->end = end;
> +
> + return 0;
> +}
> +
> +static int vfio_insert_iova(phys_addr_t start, phys_addr_t end,
> + struct list_head *head)
> +{
> + struct vfio_iommu_iova *region;
> +
> + region = kzalloc(sizeof(*region), GFP_KERNEL);
> + if (!region)
> + return -ENOMEM;
> +
> + INIT_LIST_HEAD(®ion->list);
> + region->start = start;
> + region->end = end;
> +
> + list_add_tail(®ion->list, head);
> + return 0;
> +}
> +
> +/*
> + * Check and update iova region list in case a reserved region
> + * overlaps the iommu iova range.
> + */
> +static int vfio_update_iommu_iova_range(phys_addr_t start, phys_addr_t end,
> + struct list_head *iova)
> +{
> + struct vfio_iommu_iova *node;
> + phys_addr_t a, b;
> + int ret = 0;
> +
> + if (list_empty(iova))
> + return -ENODEV;
> +
> + node = list_last_entry(iova, struct vfio_iommu_iova, list);
> + a = node->start;
> + b = node->end;
> +
> + /* No overlap */
> + if ((start > b) || (end < a))
> + return 0;
> +
> + if (start > a)
> + ret = vfio_insert_iova(a, start - 1, &node->list);
> + if (ret)
> + goto done;
> + if (end < b)
> + ret = vfio_insert_iova(end + 1, b, &node->list);
> +
> +done:
> + list_del(&node->list);
> + kfree(node);
> +
> + return ret;
> +}
> +
> +static int vfio_resv_cmp(void *priv, struct list_head *a, struct list_head *b)
> +{
> + struct iommu_resv_region *ra, *rb;
> +
> + ra = container_of(a, struct iommu_resv_region, list);
> + rb = container_of(b, struct iommu_resv_region, list);
> +
> + if (ra->start < rb->start)
> + return -1;
> + if (ra->start > rb->start)
> + return 1;
> + return 0;
> +}
> +
> +static int vfio_build_iommu_iova_caps(struct vfio_iommu *iommu,
> + struct vfio_info_cap *caps)
> +{
> + struct iommu_resv_region *resv, *resv_next;
> + struct vfio_iommu_iova *iova, *iova_next;
> + struct list_head group_resv_regions, vfio_iova_regions;
> + struct vfio_domain *domain;
> + struct vfio_group *g;
> + phys_addr_t start, end;
> + int ret = 0;
> +
> + domain = list_first_entry(&iommu->domain_list,
> + struct vfio_domain, next);
> + /* Get the default iova range supported */
> + start = domain->domain->geometry.aperture_start;
> + end = domain->domain->geometry.aperture_end;
> + INIT_LIST_HEAD(&vfio_iova_regions);
> + vfio_insert_iova(start, end, &vfio_iova_regions);
> +
> + /* Get reserved regions if any */
> + INIT_LIST_HEAD(&group_resv_regions);
> + list_for_each_entry(g, &domain->group_list, next)
> + iommu_get_group_resv_regions(g->iommu_group,
> + &group_resv_regions);
> + list_sort(NULL, &group_resv_regions, vfio_resv_cmp);
> +
> + /* Update iova range excluding reserved regions */
> + list_for_each_entry(resv, &group_resv_regions, list) {
> + ret = vfio_update_iommu_iova_range(resv->start,
> + resv->start + resv->length - 1,
> + &vfio_iova_regions);
> + if (ret)
> + goto done;
> + }
> +
> + list_for_each_entry(iova, &vfio_iova_regions, list) {
> + ret = vfio_add_iova_cap(caps, iova->start, iova->end);
> + if (ret)
> + goto done;
> + }
> +
> +done:
> + list_for_each_entry_safe(resv, resv_next, &group_resv_regions, list)
> + kfree(resv);
> +
> + list_for_each_entry_safe(iova, iova_next, &vfio_iova_regions, list)
> + kfree(iova);
> +
> + return ret;
> +}
> +
> static long vfio_iommu_type1_ioctl(void *iommu_data,
> unsigned int cmd, unsigned long arg)
> {
> @@ -1558,8 +1703,10 @@ static long vfio_iommu_type1_ioctl(void
> *iommu_data,
> }
> } else if (cmd == VFIO_IOMMU_GET_INFO) {
> struct vfio_iommu_type1_info info;
> + struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
> + int ret;
>
> - minsz = offsetofend(struct vfio_iommu_type1_info,
> iova_pgsizes);
> + minsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
>
> if (copy_from_user(&info, (void __user *)arg, minsz))
> return -EFAULT;
> @@ -1571,6 +1718,29 @@ static long vfio_iommu_type1_ioctl(void
> *iommu_data,
>
> info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
>
> + ret = vfio_build_iommu_iova_caps(iommu, &caps);
> + if (ret)
> + return ret;
> +
> + if (caps.size) {
> + info.flags |= VFIO_IOMMU_INFO_CAPS;
> + if (info.argsz < sizeof(info) + caps.size) {
> + info.argsz = sizeof(info) + caps.size;
> + info.cap_offset = 0;
> + } else {
> + vfio_info_cap_shift(&caps, sizeof(info));
> + if (copy_to_user((void __user *)arg +
> + sizeof(info), caps.buf,
> + caps.size)) {
> + kfree(caps.buf);
> + return -EFAULT;
> + }
> + info.cap_offset = sizeof(info);
> + }
> +
> + kfree(caps.buf);
> + }
> +
> return copy_to_user((void __user *)arg, &info, minsz) ?
> -EFAULT : 0;
>
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index e3301db..c4e338b 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -517,7 +517,20 @@ struct vfio_iommu_type1_info {
> __u32 argsz;
> __u32 flags;
> #define VFIO_IOMMU_INFO_PGSIZES (1 << 0) /* supported page sizes info */
> +#define VFIO_IOMMU_INFO_CAPS (1 << 1) /* Info supports caps */
> __u64 iova_pgsizes; /* Bitmap of supported page sizes */
> + __u32 cap_offset; /* Offset within info struct of first cap */
> + __u32 __resv;
> +};
> +
> +/*
> + * The IOVA_RANGE capability allows to report the IOVA range(s),
> + */
> +#define VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE 1
> +struct vfio_iommu_type1_info_cap_iova_range {
> + struct vfio_info_cap_header header;
> + __u64 start;
> + __u64 end;
> };
>
> #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
> --
> 1.9.1
>
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