[PATCH] hw/i386/intel_iommu: Simplify vtd_find_as_from_bus_num() logic

[Philippe Mathieu-Daudé]

Reorder the if() statement to simplify the function.
This avoid bugs like the one fixed by commit a2e1cd41ccf.

Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 hw/i386/intel_iommu.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 6258c58ac9..e720a8939c 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -987,14 +987,17 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, 
uint32_t level)
 static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState *s, uint8_t bus_num)
 {
     VTDBus *vtd_bus = s->vtd_as_by_bus_num[bus_num];
-    if (!vtd_bus) {
+    GHashTableIter iter;
+
+    if (vtd_bus) {
+        return vtd_bus;
+    }
+
     /*
      * Iterate over the registered buses to find the one which
      * currently hold this bus number, and update the bus_num
      * lookup table:
      */
-        GHashTableIter iter;
-
     g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
     while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
         if (pci_bus_num(vtd_bus->bus) == bus_num) {
@@ -1002,9 +1005,8 @@ static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState 
*s, uint8_t bus_num)
             return vtd_bus;
         }
     }
-        vtd_bus = NULL;
-    }
-    return vtd_bus;
+
+    return NULL;
 }
 
 /* Given the @iova, get relevant @slptep. @slpte_level will be the last level
-- 
2.21.1