intel_iommu_accel: Handle PASID entry removal for pc_inv_dsc request

When guest deletes PASID entries, QEMU will capture the pasid cache
invalidation request, walk through pasid_cache_list in each passthrough
device to find stale VTDAccelPASIDCacheEntry and delete them.

Co-developed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260527054658.1021096-13-zhenzhong.duan@intel.com>

diff --git a/hw/i386/intel_iommu_accel.c b/hw/i386/intel_iommu_accel.c
index d2653f22eecc9c7b2e4c4fd48cea403c658ac439..ed0d6bda7ecbba652401b437fdb66e43796f2802 100644 (file)
--- a/hw/i386/intel_iommu_accel.c
+++ b/hw/i386/intel_iommu_accel.c
@@ -280,6 +280,59 @@ static void vtd_accel_fill_pc(VTDHostIOMMUDevice *vtd_hiod, uint32_t pasid,
     QLIST_INSERT_HEAD(&vtd_hiod->pasid_cache_list, vtd_pce, next);
 }
 
+static void vtd_accel_delete_pc(VTDAccelPASIDCacheEntry *vtd_pce)
+{
+    QLIST_REMOVE(vtd_pce, next);
+    g_free(vtd_pce);
+}
+
+static void
+vtd_accel_pasid_cache_invalidate_one(VTDAccelPASIDCacheEntry *vtd_pce,
+                                     VTDPASIDCacheInfo *pc_info)
+{
+    VTDHostIOMMUDevice *vtd_hiod = vtd_pce->vtd_hiod;
+    VTDPASIDEntry pe;
+    uint16_t did;
+
+    /*
+     * VTD_INV_DESC_PASIDC_G_DSI and VTD_INV_DESC_PASIDC_G_PASID_SI require
+     * DID check. If DID doesn't match the value in cache or memory, then
+     * it's not a pasid entry we want to invalidate.
+     */
+    switch (pc_info->type) {
+    case VTD_INV_DESC_PASIDC_G_PASID_SI:
+        if (pc_info->pasid != vtd_pce->pasid) {
+            return;
+        }
+        /* Fall through */
+    case VTD_INV_DESC_PASIDC_G_DSI:
+        did = VTD_SM_PASID_ENTRY_DID(&vtd_pce->pasid_entry);
+        if (pc_info->did != did) {
+            return;
+        }
+    }
+
+    if (vtd_dev_get_pe_from_pasid(vtd_hiod->iommu_state, vtd_hiod->bus,
+                                  vtd_hiod->devfn, vtd_pce->pasid, &pe)) {
+        /*
+         * No valid pasid entry in guest memory. e.g. pasid entry was modified
+         * to be either all-zero or non-present. Either case means existing
+         * pasid cache should be invalidated.
+         */
+        vtd_accel_delete_pc(vtd_pce);
+    }
+}
+
+static void vtd_accel_pasid_cache_invalidate(VTDHostIOMMUDevice *vtd_hiod,
+                                             VTDPASIDCacheInfo *pc_info)
+{
+    VTDAccelPASIDCacheEntry *vtd_pce, *next;
+
+    QLIST_FOREACH_SAFE(vtd_pce, &vtd_hiod->pasid_cache_list, next, next) {
+        vtd_accel_pasid_cache_invalidate_one(vtd_pce, pc_info);
+    }
+}
+
 /*
  * This function walks over PASID range within [start, end) in a single
  * PASID table for entries matching @info type/did, then create
@@ -411,6 +464,14 @@ void vtd_accel_pasid_cache_sync(IntelIOMMUState *s, VTDPASIDCacheInfo *pc_info)
                                  TYPE_HOST_IOMMU_DEVICE_IOMMUFD)) {
             continue;
         }
+
+        /*
+         * The replay path inevitably needs to iterate through existing
+         * PASID cache entries. Since cached PASID entries that are marked
+         * for removal don't need to be iterated, we intentionally handle
+         * removals before additions to optimize the replay process.
+         */
+        vtd_accel_pasid_cache_invalidate(vtd_hiod, pc_info);
         vtd_accel_replay_pasid_bind_for_dev(vtd_hiod, start, end, pc_info);
     }
 }