[PULL 18/19] hw/i386/amd_iommu: Don't leak memory in amdvi_update_iotlb()

["Michael S. Tsirkin" <mst@redhat.com>]

From: Peter Maydell <peter.maydell@linaro.org>

In amdvi_update_iotlb() we will only put a new entry in the hash
table if to_cache.perm is not IOMMU_NONE.  However we allocate the
memory for the new AMDVIIOTLBEntry and for the hash table key
regardless.  This means that in the IOMMU_NONE case we will leak the
memory we alloacted.

Move the allocations into the if() to the point where we know we're
going to add the item to the hash table.

Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2452
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20240731170019.3590563-1-peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/i386/amd_iommu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 6d4fde72f9..87643d2891 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -357,12 +357,12 @@ static void amdvi_update_iotlb(AMDVIState *s, uint16_t devid,
                                uint64_t gpa, IOMMUTLBEntry to_cache,
                                uint16_t domid)
 {
-    AMDVIIOTLBEntry *entry = g_new(AMDVIIOTLBEntry, 1);
-    uint64_t *key = g_new(uint64_t, 1);
-    uint64_t gfn = gpa >> AMDVI_PAGE_SHIFT_4K;
-
     /* don't cache erroneous translations */
     if (to_cache.perm != IOMMU_NONE) {
+        AMDVIIOTLBEntry *entry = g_new(AMDVIIOTLBEntry, 1);
+        uint64_t *key = g_new(uint64_t, 1);
+        uint64_t gfn = gpa >> AMDVI_PAGE_SHIFT_4K;
+
         trace_amdvi_cache_update(domid, PCI_BUS_NUM(devid), PCI_SLOT(devid),
                 PCI_FUNC(devid), gpa, to_cache.translated_addr);
 
-- 
MST