amd_iommu: Fix truncation of oldval in amdvi_writeq

The variable `oldval` was incorrectly declared as a 32-bit `uint32_t`.
This could lead to truncation and incorrect behavior where the upper
read-only 32 bits are significant.

Fix the type of `oldval` to match the return type of `ldq_le_p()`.

Cc: qemu-stable@nongnu.org
Fixes: d29a09ca6842 ("hw/i386: Introduce AMD IOMMU")
Signed-off-by: Ethan Milon <ethan.milon@eviden.com>
Message-Id: <20250617150427.20585-9-alejandro.j.jimenez@oracle.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 92f94dc788c3df8e3a9e3f81dcf48c8036240056..5a24c17548d459e644a0f7a2cf320c13f9f1d5ee 100644 (file)
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -140,7 +140,7 @@ static void amdvi_writeq(AMDVIState *s, hwaddr addr, uint64_t val)
 {
     uint64_t romask = ldq_le_p(&s->romask[addr]);
     uint64_t w1cmask = ldq_le_p(&s->w1cmask[addr]);
-    uint32_t oldval = ldq_le_p(&s->mmior[addr]);
+    uint64_t oldval = ldq_le_p(&s->mmior[addr]);
     stq_le_p(&s->mmior[addr],
             ((oldval & romask) | (val & ~romask)) & ~(val & w1cmask));
 }