[PATCH v1 09/22] vfio/common: check PASID alloc/free availability

Liu Yi L
2020-03-22T12:31:06Z

VFIO exposes host IOMMU dual-stage DMA translation programming capability
to userspace by VFIO_TYPE1_NESTING_IOMMU type. However, userspace needs
more info on the nesting type. e.g. the supported stage 1 format and PASID
alloc/free request availability.

This patch gets the iommu nesting cap info from kernel by using IOCTL
VFIO_IOMMU_GET_INFO. And checks the HOST_IOMMU_PASID_REQUEST bit in the
nesting capabilities.

This patch referred some code from Shameer Kolothum.
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg03759.html

Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Yi Sun <yi.y.sun@linux.intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
hw/vfio/common.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 91 insertions(+), 5 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index e4f5f10..e0f2828 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1223,6 +1223,84 @@ static int vfio_host_icx_pasid_free(HostIOMMUContext *host_icx,
return 0;
}

+/**
+ * Get iommu info from host. Caller of this funcion should free
+ * the memory pointed by the returned pointer stored in @info
+ * after a successful calling when finished its usage.
+ */
+static int vfio_get_iommu_info(VFIOContainer *container,
+ struct vfio_iommu_type1_info **info)
+{
+
+ size_t argsz = sizeof(struct vfio_iommu_type1_info);
+
+ *info = g_malloc0(argsz);
+
+retry:
+ (*info)->argsz = argsz;
+
+ if (ioctl(container->fd, VFIO_IOMMU_GET_INFO, *info)) {
+ g_free(*info);
+ *info = NULL;
+ return -errno;
+ }
+
+ if (((*info)->argsz > argsz)) {
+ argsz = (*info)->argsz;
+ *info = g_realloc(*info, argsz);
+ goto retry;
+ }
+
+ return 0;
+}
+
+static struct vfio_info_cap_header *
+vfio_get_iommu_info_cap(struct vfio_iommu_type1_info *info, uint16_t id)
+{
+ struct vfio_info_cap_header *hdr;
+ void *ptr = info;
+
+ if (!(info->flags & VFIO_IOMMU_INFO_CAPS)) {
+ return NULL;
+ }
+
+ for (hdr = ptr + info->cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
+ if (hdr->id == id) {
+ return hdr;
+ }
+ }
+
+ return NULL;
+}
+
+static int vfio_get_nesting_iommu_cap(VFIOContainer *container,
+ struct vfio_iommu_type1_info_cap_nesting *cap_nesting)
+{
+ struct vfio_iommu_type1_info *info;
+ struct vfio_info_cap_header *hdr;
+ struct vfio_iommu_type1_info_cap_nesting *cap;
+ int ret;
+
+ ret = vfio_get_iommu_info(container, &info);
+ if (ret) {
+ return ret;
+ }
+
+ hdr = vfio_get_iommu_info_cap(info,
+ VFIO_IOMMU_TYPE1_INFO_CAP_NESTING);
+ if (!hdr) {
+ g_free(info);
+ return -errno;
+ }
+
+ cap = container_of(hdr,
+ struct vfio_iommu_type1_info_cap_nesting, header);
+ *cap_nesting = *cap;
+
+ g_free(info);
+ return 0;
+}
+
static int vfio_init_container(VFIOContainer *container, int group_fd,
Error **errp)
{
@@ -1256,11 +1334,19 @@ static int vfio_init_container(VFIOContainer *container, int group_fd,
}

if (iommu_type == VFIO_TYPE1_NESTING_IOMMU) {
- /*
- * TODO: config flags per host IOMMU nesting capability
- * e.g. check if VFIO_TYPE1_NESTING_IOMMU supports PASID
- * alloc/free
- */
+ struct vfio_iommu_type1_info_cap_nesting nesting = {
+ .nesting_capabilities = 0x0,
+ .stage1_formats = 0, };
+
+ ret = vfio_get_nesting_iommu_cap(container, &nesting);
+ if (ret) {
+ error_setg_errno(errp, -ret,
+ "Failed to get nesting iommu cap");
+ return ret;
+ }
+
+ flags |= (nesting.nesting_capabilities & VFIO_IOMMU_PASID_REQS) ?
+ HOST_IOMMU_PASID_REQUEST : 0;
host_iommu_ctx_init(&container->host_icx,
sizeof(container->host_icx),
TYPE_VFIO_HOST_IOMMU_CONTEXT,
--
2.7.4