[Qemu-devel] [PULL 10/11] memory: Fix IOMMU replay base address

[Alex Williamson <alex.williamson@redhat.com>]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

Since a788f227 "memory: Allow replay of IOMMU mapping notifications"
when new VFIO listener is added, all existing IOMMU mappings are
replayed. However there is a problem that the base address of
an IOMMU memory region (IOMMU MR) is ignored which is not a problem
for the existing user (which is pseries) with its default 32bit DMA
window starting at 0 but it is if there is another DMA window.

This stores the IOMMU's offset_within_address_space and adjusts
the IOVA before calling vfio_dma_map/vfio_dma_unmap.

As the IOMMU notifier expects IOVA offset rather than the absolute
address, this also adjusts IOVA in sPAPR H_PUT_TCE handler before
calling notifier(s).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/ppc/spapr_iommu.c          |    2 +-
 hw/vfio/common.c              |   14 ++++++++------
 include/hw/vfio/vfio-common.h |    1 +
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index 722db91..b6fe1dd 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -278,7 +278,7 @@ static target_ulong put_tce_emu(sPAPRTCETable *tcet, target_ulong ioba,
     tcet->table[index] = tce;
 
     entry.target_as = &address_space_memory,
-    entry.iova = ioba & page_mask;
+    entry.iova = (ioba - tcet->bus_offset) & page_mask;
     entry.translated_addr = tce & page_mask;
     entry.addr_mask = ~page_mask;
     entry.perm = spapr_tce_iommu_access_flags(tce);
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 29f8f84..e2d5a8d 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -260,14 +260,14 @@ static void vfio_iommu_map_notify(Notifier *n, void *data)
     VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
     VFIOContainer *container = giommu->container;
     IOMMUTLBEntry *iotlb = data;
+    hwaddr iova = iotlb->iova + giommu->iommu_offset;
     MemoryRegion *mr;
     hwaddr xlat;
     hwaddr len = iotlb->addr_mask + 1;
     void *vaddr;
     int ret;
 
-    trace_vfio_iommu_map_notify(iotlb->iova,
-                                iotlb->iova + iotlb->addr_mask);
+    trace_vfio_iommu_map_notify(iova, iova + iotlb->addr_mask);
 
     /*
      * The IOMMU TLB entry we have just covers translation through
@@ -294,21 +294,21 @@ static void vfio_iommu_map_notify(Notifier *n, void *data)
 
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
         vaddr = memory_region_get_ram_ptr(mr) + xlat;
-        ret = vfio_dma_map(container, iotlb->iova,
+        ret = vfio_dma_map(container, iova,
                            iotlb->addr_mask + 1, vaddr,
                            !(iotlb->perm & IOMMU_WO) || mr->readonly);
         if (ret) {
             error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx", %p) = %d (%m)",
-                         container, iotlb->iova,
+                         container, iova,
                          iotlb->addr_mask + 1, vaddr, ret);
         }
     } else {
-        ret = vfio_dma_unmap(container, iotlb->iova, iotlb->addr_mask + 1);
+        ret = vfio_dma_unmap(container, iova, iotlb->addr_mask + 1);
         if (ret) {
             error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx") = %d (%m)",
-                         container, iotlb->iova,
+                         container, iova,
                          iotlb->addr_mask + 1, ret);
         }
     }
@@ -380,6 +380,8 @@ static void vfio_listener_region_add(MemoryListener *listener,
          */
         giommu = g_malloc0(sizeof(*giommu));
         giommu->iommu = section->mr;
+        giommu->iommu_offset = section->offset_within_address_space -
+                               section->offset_within_region;
         giommu->container = container;
         giommu->n.notify = vfio_iommu_map_notify;
         QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index a947f9c..0610377 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -90,6 +90,7 @@ typedef struct VFIOContainer {
 typedef struct VFIOGuestIOMMU {
     VFIOContainer *container;
     MemoryRegion *iommu;
+    hwaddr iommu_offset;
     Notifier n;
     QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
 } VFIOGuestIOMMU;