[PATCH v7 17/19] vfio/type1: Allow transparent MSI IOVA allocation

Eric Auger
2017-01-09T13:47:56Z

When attaching a group to the container, check the group's
reserved regions and test whether the IOMMU translates MSI
transactions. If yes, we initialize an IOVA allocator through
the iommu_get_msi_cookie API. This will allow the MSI IOVAs
to be transparently allocated on MSI controller's compose().

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v3 -> v4:
- test region's type: IOMMU_RESV_MSI
- restructure the code to prepare for safety assessment
- reword title
---
drivers/vfio/vfio_iommu_type1.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 9266271..5651faf 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -39,6 +39,7 @@
#include <linux/pid_namespace.h>
#include <linux/mdev.h>
#include <linux/notifier.h>
+#include <linux/dma-iommu.h>

#define DRIVER_VERSION "0.2"
#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>"
@@ -1181,6 +1182,28 @@ static struct vfio_group *find_iommu_group(struct vfio_domain *domain,
return NULL;
}

+static bool vfio_iommu_has_resv_msi(struct iommu_group *group,
+ phys_addr_t *base)
+{
+ struct list_head group_resv_regions;
+ struct iommu_resv_region *region, *next;
+ bool ret = false;
+
+ INIT_LIST_HEAD(&group_resv_regions);
+ iommu_get_group_resv_regions(group, &group_resv_regions);
+ list_for_each_entry(region, &group_resv_regions, list) {
+ if (region->type & IOMMU_RESV_MSI) {
+ *base = region->start;
+ ret = true;
+ goto out;
+ }
+ }
+out:
+ list_for_each_entry_safe(region, next, &group_resv_regions, list)
+ kfree(region);
+ return ret;
+}
+
static int vfio_iommu_type1_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
@@ -1189,6 +1212,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
struct vfio_domain *domain, *d;
struct bus_type *bus = NULL, *mdev_bus;
int ret;
+ bool resv_msi;
+ phys_addr_t resv_msi_base;

mutex_lock(&iommu->lock);

@@ -1258,6 +1283,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
if (ret)
goto out_domain;

+ resv_msi = vfio_iommu_has_resv_msi(iommu_group, &resv_msi_base);
+
INIT_LIST_HEAD(&domain->group_list);
list_add(&group->next, &domain->group_list);

@@ -1304,6 +1331,9 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
if (ret)
goto out_detach;

+ if (resv_msi && iommu_get_msi_cookie(domain->domain, resv_msi_base))
+ goto out_detach;
+
list_add(&domain->next, &iommu->domain_list);

mutex_unlock(&iommu->lock);
--
1.9.1