[PATCH v5 5/7] vfio/type1: Add IOVA range capability support

Shameer Kolothum
2018-03-15T16:35:07Z

This allows the user-space to retrieve the supported IOVA
range(s), excluding any reserved regions. The implementation
is based on capability chains, added to VFIO_IOMMU_GET_INFO ioctl.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
drivers/vfio/vfio_iommu_type1.c | 96 +++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 23 ++++++++++
2 files changed, 119 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d59db31..90f195d 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1929,6 +1929,68 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
return ret;
}

+static int vfio_iommu_iova_add_cap(struct vfio_info_cap *caps,
+ struct vfio_iommu_type1_info_cap_iova_range *cap_iovas,
+ size_t size)
+{
+ struct vfio_info_cap_header *header;
+ struct vfio_iommu_type1_info_cap_iova_range *iova_cap;
+
+ header = vfio_info_cap_add(caps, size,
+ VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE, 1);
+ if (IS_ERR(header))
+ return PTR_ERR(header);
+
+ iova_cap = container_of(header,
+ struct vfio_iommu_type1_info_cap_iova_range, header);
+ iova_cap->nr_iovas = cap_iovas->nr_iovas;
+ memcpy(iova_cap->iova_ranges, cap_iovas->iova_ranges,
+ cap_iovas->nr_iovas * sizeof(*cap_iovas->iova_ranges));
+ return 0;
+}
+
+static int vfio_iommu_iova_build_caps(struct vfio_iommu *iommu,
+ struct vfio_info_cap *caps)
+{
+ struct vfio_iommu_type1_info_cap_iova_range *cap_iovas;
+ struct vfio_iova *iova;
+ size_t size;
+ int iovas = 0, i = 0, ret;
+
+ mutex_lock(&iommu->lock);
+
+ list_for_each_entry(iova, &iommu->iova_list, list)
+ iovas++;
+
+ if (!iovas) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ size = sizeof(*cap_iovas) + (iovas * sizeof(*cap_iovas->iova_ranges));
+
+ cap_iovas = kzalloc(size, GFP_KERNEL);
+ if (!cap_iovas) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ cap_iovas->nr_iovas = iovas;
+
+ list_for_each_entry(iova, &iommu->iova_list, list) {
+ cap_iovas->iova_ranges[i].start = iova->start;
+ cap_iovas->iova_ranges[i].end = iova->end;
+ i++;
+ }
+
+ ret = vfio_iommu_iova_add_cap(caps, cap_iovas, size);
+
+ kfree(cap_iovas);
+out_unlock:
+ mutex_unlock(&iommu->lock);
+ return ret;
+}
+
static long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
@@ -1950,19 +2012,53 @@ 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 };
+ unsigned long capsz;
+ int ret;

minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);

+ /* For backward compatibility, cannot require this */
+ capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
+
if (copy_from_user(&info, (void __user *)arg, minsz))
return -EFAULT;

if (info.argsz < minsz)
return -EINVAL;

+ if (info.argsz >= capsz) {
+ minsz = capsz;
+ info.cap_offset = 0; /* output, no-recopy necessary */
+ }
+
info.flags = VFIO_IOMMU_INFO_PGSIZES;

info.iova_pgsizes = vfio_pgsize_bitmap(iommu);

+ ret = vfio_iommu_iova_build_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;
+ } 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 c743721..46b49e9 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -589,7 +589,30 @@ 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 */
+};
+
+/*
+ * The IOVA capability allows to report the valid IOVA range(s)
+ * excluding any reserved regions associated with dev group. Any dma
+ * map attempt outside the valid iova range will return error.
+ *
+ * The structures below define version 1 of this capability.
+ */
+#define VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE 1
+
+struct vfio_iova_range {
+ __u64 start;
+ __u64 end;
+};
+
+struct vfio_iommu_type1_info_cap_iova_range {
+ struct vfio_info_cap_header header;
+ __u32 nr_iovas;
+ __u32 reserved;
+ struct vfio_iova_range iova_ranges[];
};

#define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
--
2.7.4