[Qemu-devel] [RFC v9 13/17] virtio_iommu: Handle reserved regions in translation process

[Eric Auger <eric.auger@redhat.com>]

When translating an address we need to check if it belongs to
a reserved virtual address range. If it does, there are 2 cases:

- it belongs to a RESERVED region: the guest should neither use
  this address in a MAP not instruct the end-point to DMA on
  them. We report an error

- It belongs to an MSI region: we bypass the translation.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 hw/virtio/virtio-iommu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 1246dd6bdf..2ec01f3b9e 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -740,6 +740,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     viommu_interval interval;
     bool bypass_allowed;
     bool read_fault, write_fault;
+    struct virtio_iommu_probe_resv_mem *reg;
 
     interval.low = addr;
     interval.high = addr + 1;
@@ -772,6 +773,21 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
         goto unlock;
     }
 
+    reg = g_tree_lookup(ep->reserved_regions, (gpointer)(&interval));
+    if (reg) {
+        switch (reg->subtype) {
+        case VIRTIO_IOMMU_RESV_MEM_T_MSI:
+            entry.perm = flag;
+            break;
+        case VIRTIO_IOMMU_RESV_MEM_T_RESERVED:
+        default:
+            virtio_iommu_report_fault(s, VIRTIO_IOMMU_FAULT_R_MAPPING,
+                                      0, sid, addr);
+            break;
+        }
+        goto unlock;
+    }
+
     if (!ep->domain) {
         if (!bypass_allowed) {
             qemu_log_mask(LOG_GUEST_ERROR,
-- 
2.17.2