[PATCH 4/4] vfio: vfio_iommu_type1: implement VFIO_IOMMU_INFO_CAPABILITIES

Pierre Morel
2019-05-10T08:22:35Z

We implement a capability intercafe for VFIO_IOMMU_GET_INFO and add the
first capability: VFIO_IOMMU_INFO_CAPABILITIES.

When calling the ioctl, the user must specify
VFIO_IOMMU_INFO_CAPABILITIES to retrieve the capabilities and must check
in the answer if capabilities are supported.
Older kernel will not check nor set the VFIO_IOMMU_INFO_CAPABILITIES in
the flags of vfio_iommu_type1_info.

The iommu get_attr callback will be called to retrieve the specific
attributes and fill the capabilities, VFIO_IOMMU_INFO_CAP_QFN for the
PCI query function attributes and VFIO_IOMMU_INFO_CAP_QGRP for the
PCI query function group.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
drivers/vfio/vfio_iommu_type1.c | 95 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 94 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d0f731c..f7f8120 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1658,6 +1658,70 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
return ret;
}

+int vfio_iommu_type1_caps(struct vfio_iommu *iommu, struct vfio_info_cap *caps,
+ size_t size)
+{
+ struct vfio_domain *d;
+ struct vfio_iommu_type1_info_block *info_fn;
+ struct vfio_iommu_type1_info_block *info_grp;
+ unsigned long total_size, fn_size, grp_size;
+ int ret;
+
+ d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
+ if (!d)
+ return -ENODEV;
+ /* The size of these capabilities are device dependent */
+ fn_size = iommu_domain_get_attr(d->domain,
+ DOMAIN_ATTR_ZPCI_FN_SIZE, NULL);
+ if (fn_size < 0)
+ return fn_size;
+ fn_size += sizeof(struct vfio_info_cap_header);
+ total_size = fn_size;
+
+ grp_size = iommu_domain_get_attr(d->domain,
+ DOMAIN_ATTR_ZPCI_GRP_SIZE, NULL);
+ if (grp_size < 0)
+ return grp_size;
+ grp_size += sizeof(struct vfio_info_cap_header);
+ total_size += grp_size;
+
+ /* Tell caller to call us with a greater buffer */
+ if (total_size > size) {
+ caps->size = total_size;
+ return 0;
+ }
+
+ info_fn = kzalloc(fn_size, GFP_KERNEL);
+ if (!info_fn)
+ return -ENOMEM;
+ ret = iommu_domain_get_attr(d->domain,
+ DOMAIN_ATTR_ZPCI_FN, &info_fn->data);
+ if (ret < 0)
+ return ret;
+
+ info_fn->header.id = VFIO_IOMMU_INFO_CAP_QFN;
+
+ ret = vfio_info_add_capability(caps, &info_fn->header, fn_size);
+ if (ret)
+ goto err_fn;
+
+ info_grp = kzalloc(grp_size, GFP_KERNEL);
+ if (!info_grp)
+ goto err_fn;
+ ret = iommu_domain_get_attr(d->domain,
+ DOMAIN_ATTR_ZPCI_GRP, &info_grp->data);
+ if (ret < 0)
+ goto err_grp;
+ info_grp->header.id = VFIO_IOMMU_INFO_CAP_QGRP;
+ ret = vfio_info_add_capability(caps, &info_grp->header, grp_size);
+
+err_grp:
+ kfree(info_grp);
+err_fn:
+ kfree(info_fn);
+ return ret;
+}
+
static long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
@@ -1679,6 +1743,8 @@ 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);

@@ -1688,7 +1754,34 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
if (info.argsz < minsz)
return -EINVAL;

- info.flags = VFIO_IOMMU_INFO_PGSIZES;
+ if (info.flags & VFIO_IOMMU_INFO_CAPABILITIES) {
+ minsz = offsetofend(struct vfio_iommu_type1_info,
+ cap_offset);
+ if (info.argsz < minsz)
+ return -EINVAL;
+ ret = vfio_iommu_type1_caps(iommu, &caps,
+ info.argsz - sizeof(info));
+ if (ret)
+ return ret;
+ }
+ if (caps.size) {
+ if (info.argsz < sizeof(info) + caps.size) {
+ info.argsz = sizeof(info) + caps.size;
+ info.cap_offset = 0;
+ } else {
+ 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);
+ }
+
+ info.flags |= VFIO_IOMMU_INFO_PGSIZES;

info.iova_pgsizes = vfio_pgsize_bitmap(iommu);

--
2.7.4