[PATCH v5 11/15] vfio/type1: Allow invalidating first-level/stage IOMMU cache

Liu Yi L
2020-07-12T11:15:46Z

This patch provides an interface allowing the userspace to invalidate
IOMMU cache for first-level page table. It is required when the first
level IOMMU page table is not managed by the host kernel in the nested
translation setup.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
v1 -> v2:
*) rename from "vfio/type1: Flush stage-1 IOMMU cache for nesting type"
*) rename vfio_cache_inv_fn() to vfio_dev_cache_invalidate_fn()
*) vfio_dev_cache_inv_fn() always successful
*) remove VFIO_IOMMU_CACHE_INVALIDATE, and reuse VFIO_IOMMU_NESTING_OP
---
drivers/vfio/vfio_iommu_type1.c | 50 +++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 3 +++
2 files changed, 53 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index f0f21ff..960cc59 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -3073,6 +3073,53 @@ static long vfio_iommu_handle_pgtbl_op(struct vfio_iommu *iommu,
return ret;
}

+static int vfio_dev_cache_invalidate_fn(struct device *dev, void *data)
+{
+ struct domain_capsule *dc = (struct domain_capsule *)data;
+ unsigned long arg = *(unsigned long *)dc->data;
+
+ iommu_cache_invalidate(dc->domain, dev, (void __user *)arg);
+ return 0;
+}
+
+static long vfio_iommu_invalidate_cache(struct vfio_iommu *iommu,
+ unsigned long arg)
+{
+ struct domain_capsule dc = { .data = &arg };
+ struct vfio_group *group;
+ struct vfio_domain *domain;
+ int ret = 0;
+ struct iommu_nesting_info *info;
+
+ mutex_lock(&iommu->lock);
+ /*
+ * Cache invalidation is required for any nesting IOMMU,
+ * so no need to check system-wide PASID support.
+ */
+ info = iommu->nesting_info;
+ if (!info || !(info->features & IOMMU_NESTING_FEAT_CACHE_INVLD)) {
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
+ }
+
+ group = vfio_find_nesting_group(iommu);
+ if (!group) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ domain = list_first_entry(&iommu->domain_list,
+ struct vfio_domain, next);
+ dc.group = group;
+ dc.domain = domain->domain;
+ iommu_group_for_each_dev(group->iommu_group, &dc,
+ vfio_dev_cache_invalidate_fn);
+
+out_unlock:
+ mutex_unlock(&iommu->lock);
+ return ret;
+}
+
static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
unsigned long arg)
{
@@ -3095,6 +3142,9 @@ static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
case VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL:
ret = vfio_iommu_handle_pgtbl_op(iommu, false, arg + minsz);
break;
+ case VFIO_IOMMU_NESTING_OP_CACHE_INVLD:
+ ret = vfio_iommu_invalidate_cache(iommu, arg + minsz);
+ break;
default:
ret = -EINVAL;
}
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index a8ad786..845a5800 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1225,6 +1225,8 @@ struct vfio_iommu_type1_pasid_request {
* +-----------------+-----------------------------------------------+
* | UNBIND_PGTBL | struct iommu_gpasid_bind_data |
* +-----------------+-----------------------------------------------+
+ * | CACHE_INVLD | struct iommu_cache_invalidate_info |
+ * +-----------------+-----------------------------------------------+
*
* returns: 0 on success, -errno on failure.
*/
@@ -1237,6 +1239,7 @@ struct vfio_iommu_type1_nesting_op {

#define VFIO_IOMMU_NESTING_OP_BIND_PGTBL (0)
#define VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL (1)
+#define VFIO_IOMMU_NESTING_OP_CACHE_INVLD (2)

#define VFIO_IOMMU_NESTING_OP _IO(VFIO_TYPE, VFIO_BASE + 19)

--
2.7.4