[Qemu-devel] [PATCH v6 3/7] vfio: Fix 128 bit handling

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Upcoming VFIO on SPAPR PPC64 support will initialize the IOMMU
memory region with UINT64_MAX (2^64 bytes) size so int128_get64()
will assert.

The patch takes care of this check. The existing type1 IOMMU code
is not expected to map all 64 bits of RAM so the patch does not
touch that part.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

---
Changes:
v3:
* 64bit @end is calculated from 128-bit @llend instead of repeating
the same calculation steps

v2:
* used new function int128_exts64()
---
 hw/misc/vfio.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 9cf5b84..3ff776a 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -2248,6 +2248,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
     VFIOContainer *container = container_of(listener, VFIOContainer,
                                             iommu_data.type1.listener);
     hwaddr iova, end;
+    Int128 llend;
     void *vaddr;
     int ret;
 
@@ -2268,13 +2269,15 @@ static void vfio_listener_region_add(MemoryListener *listener,
     }
 
     iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
-    end = (section->offset_within_address_space + int128_get64(section->size)) &
-          TARGET_PAGE_MASK;
+    llend = int128_make64(section->offset_within_address_space);
+    llend = int128_add(llend, section->size);
+    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
 
-    if (iova >= end) {
+    if (int128_ge(int128_make64(iova), llend)) {
         return;
     }
 
+    end = int128_get64(llend);
     vaddr = memory_region_get_ram_ptr(section->mr) +
             section->offset_within_region +
             (iova - section->offset_within_address_space);
-- 
1.9.rc0