[Stable-7.2.14 20/40] hw/i386/amd_iommu: Don't leak memory in amdvi_update_iotlb()

[Michael Tokarev]

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>
(cherry picked from commit 9a45b0761628cc59267b3283a85d15294464ac31)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index a20f3e1d50..02597db1e1 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -346,12 +346,12 @@ 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);
 
-- 
2.39.2