Introduce an helper function to retrieve the iommu type1 capability
chain info.
The first capability ready to be exploited is the msi resv
capability. vfio_prepare_msi_mapping allocates a MemoryRegion
dedicated to host MSI IOVA mapping. Its size matches the host needs.
This region is mapped on guest side on the platform bus memory container.
Signed-off-by: Eric Auger <eric.au...@redhat.com>
---
v4 -> v5:
- use msi_resv struct
v3 -> v4:
- initialize err to NULL
v3: creation
---
hw/vfio/common.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4f4014e..1e2282c 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -34,6 +34,8 @@
#include "qemu/range.h"
#include "sysemu/kvm.h"
#include "trace.h"
+#include "hw/platform-bus.h"
+#include "qapi/error.h"
struct vfio_group_head vfio_group_list =
QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -920,12 +922,70 @@ retry:
return 0;
}
+static struct vfio_info_cap_header *
+vfio_get_iommu_type1_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 void vfio_prepare_msi_mapping(struct vfio_iommu_type1_info *info,
+ AddressSpace *as, Error **errp)
+{
+ struct vfio_iommu_type1_info_cap_msi_resv *msi_resv;
+ MemoryRegion *pbus_region, *reserved_reg;
+ struct vfio_info_cap_header *hdr;
+ PlatformBusDevice *pbus;
+
+ hdr = vfio_get_iommu_type1_info_cap(info,
+ VFIO_IOMMU_TYPE1_INFO_CAP_MSI_RESV);
+ if (!hdr) {
+ return;
+ }
+
+ msi_resv = container_of(hdr, struct vfio_iommu_type1_info_cap_msi_resv,
+ header);
+ /*
+ * MSI must be iommu mapped: allocate a GPA region located on the
+ * platform bus that the host will be able to use for MSI IOVA allocation
+ */
+ reserved_reg = memory_region_find_by_name(as->root, "reserved-iova");
+ if (reserved_reg) {
+ memory_region_unref(reserved_reg);
+ return;
+ }
+
+ pbus_region = memory_region_find_by_name(as->root, "platform bus");
+ if (!pbus_region) {
+ error_setg(errp, "no platform bus memory container found");
+ return;
+ }
+ pbus = container_of(pbus_region, PlatformBusDevice, mmio);
+ reserved_reg = g_new0(MemoryRegion, 1);
+ memory_region_init_reserved_iova(reserved_reg, OBJECT(pbus),
+ "reserved-iova",
+ msi_resv->size, &error_fatal);
+ platform_bus_map_region(pbus, reserved_reg);
+ memory_region_unref(pbus_region);
+}
static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
{
VFIOContainer *container;
int ret, fd;
VFIOAddressSpace *space;
+ Error *err = NULL;
space = vfio_get_address_space(as);
@@ -983,6 +1043,14 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
* going to actually try in practice.
*/
vfio_get_iommu_type1_info(fd, &pinfo);
+ vfio_prepare_msi_mapping(pinfo, as, &err);
+ if (err) {
+ error_append_hint(&err,
+ "Make sure your machine instantiates a platform bus\n");
+ error_report_err(err);
+ goto free_container_exit;
+ }
+
/* Ignore errors */
if (ret || !(pinfo->flags & VFIO_IOMMU_INFO_PGSIZES)) {
/* Assume 4k IOVA page size */
--
1.9.1
