From: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>

When the kernel IOMMU driver issues an INVALIDATE_IOMMU_ALL, the address
translation and interrupt remapping information must be cleared for all
Device IDs and all domains. Introduce a helper to sync the shadow page table
for all the address spaces with registered notifiers, which replays both MAP
and UNMAP events.

Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20250919213515.917111-15-alejandro.j.jimenez@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/i386/amd_iommu.c | 48 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 9027f7c054..d74d42b3dd 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -941,6 +941,47 @@ static void amdvi_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n)
     amdvi_sync_shadow_page_table_range(as, &dte[0], 0, UINT64_MAX, false);
 }
 
+static void amdvi_address_space_sync(AMDVIAddressSpace *as)
+{
+    IOMMUNotifier *n;
+    uint64_t dte[4] = { 0 };
+
+    /* If only UNMAP notifiers are registered, drop all existing mappings */
+    if (!(as->notifier_flags & IOMMU_NOTIFIER_MAP)) {
+        IOMMU_NOTIFIER_FOREACH(n, &as->iommu) {
+            /*
+             * Directly calling memory_region_unmap_iommu_notifier_range() does
+             * not guarantee that the addr_mask eventually passed as parameter
+             * to the notifier is valid. Use amdvi_address_space_unmap() which
+             * ensures the notifier range is divided into properly aligned
+             * regions, and issues notifications for each one.
+             */
+            amdvi_address_space_unmap(as, n);
+        }
+        return;
+    }
+
+    if (amdvi_as_to_dte(as, dte)) {
+        return;
+    }
+
+    amdvi_sync_shadow_page_table_range(as, &dte[0], 0, UINT64_MAX, true);
+}
+
+/*
+ * This differs from the replay() method in that it issues both MAP and UNMAP
+ * notifications since it is called after global invalidation events in order to
+ * re-sync all address spaces.
+ */
+static void amdvi_iommu_address_space_sync_all(AMDVIState *s)
+{
+    AMDVIAddressSpace *as;
+
+    QLIST_FOREACH(as, &s->amdvi_as_with_notifiers, next) {
+        amdvi_address_space_sync(as);
+    }
+}
+
 /* log error without aborting since linux seems to be using reserved bits */
 static void amdvi_inval_devtab_entry(AMDVIState *s, uint64_t *cmd)
 {
@@ -983,6 +1024,13 @@ static void amdvi_inval_all(AMDVIState *s, uint64_t *cmd)
     amdvi_intremap_inval_notify_all(s, true, 0, 0);
 
     amdvi_iotlb_reset(s);
+
+    /*
+     * Fully replay the address space i.e. send both UNMAP and MAP events in
+     * order to synchronize guest and host IO page tables tables.
+     */
+    amdvi_iommu_address_space_sync_all(s);
+
     trace_amdvi_all_inval();
 }
 
-- 
MST