[Qemu-devel] [PATCH v4 5/5] hw/arm/smmuv3: Remove spurious error messages on IOVA invalidations

[Eric Auger <eric.auger@redhat.com>]

An IOVA/ASID invalidation is notified to all IOMMU Memory Regions
through smmuv3_inv_notifiers_iova/smmuv3_notify_iova.

When the notification occurs it is possible that some of the
PCIe devices associated to the notified regions do not have a
valid stream table entry. In that case we output a LOG_GUEST_ERROR
message, for example:

invalid sid=<SID> (L1STD span=0)
"smmuv3_notify_iova error decoding the configuration for iommu mr=<MR>

This is unfortunate as the user gets the impression that there
are some translation decoding errors whereas there are not.

This patch adds a new field in SMMUEventInfo that tells whether
the detection of an invalid STE must lead to an error report.
invalid_ste_allowed is set before doing the invalidations and
kept unset on actual translation.

The other configuration decoding error messages are kept since if the
STE is valid then the rest of the config must be correct.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v3 -> v4:
- only remove the trace on !span path but keep the error value
---
 hw/arm/smmuv3-internal.h |  1 +
 hw/arm/smmuv3.c          | 19 +++++++++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/hw/arm/smmuv3-internal.h b/hw/arm/smmuv3-internal.h
index b160289cd1..d190181ef1 100644
--- a/hw/arm/smmuv3-internal.h
+++ b/hw/arm/smmuv3-internal.h
@@ -381,6 +381,7 @@ typedef struct SMMUEventInfo {
     uint32_t sid;
     bool recorded;
     bool record_trans_faults;
+    bool inval_ste_allowed;
     union {
         struct {
             uint32_t ssid;
diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index c353e4c27b..dbcd0f2fe9 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -320,7 +320,9 @@ static int decode_ste(SMMUv3State *s, SMMUTransCfg *cfg,
     uint32_t config;
 
     if (!STE_VALID(ste)) {
-        qemu_log_mask(LOG_GUEST_ERROR, "invalid STE\n");
+        if (!event->inval_ste_allowed) {
+            qemu_log_mask(LOG_GUEST_ERROR, "invalid STE\n");
+        }
         goto bad_ste;
     }
 
@@ -407,8 +409,10 @@ static int smmu_find_ste(SMMUv3State *s, uint32_t sid, STE *ste,
 
         if (!span) {
             /* l2ptr is not valid */
-            qemu_log_mask(LOG_GUEST_ERROR,
-                          "invalid sid=%d (L1STD span=0)\n", sid);
+            if (!event->inval_ste_allowed) {
+                qemu_log_mask(LOG_GUEST_ERROR,
+                              "invalid sid=%d (L1STD span=0)\n", sid);
+            }
             event->type = SMMU_EVT_C_BAD_STREAMID;
             return -EINVAL;
         }
@@ -603,7 +607,9 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     SMMUDevice *sdev = container_of(mr, SMMUDevice, iommu);
     SMMUv3State *s = sdev->smmu;
     uint32_t sid = smmu_get_sid(sdev);
-    SMMUEventInfo event = {.type = SMMU_EVT_NONE, .sid = sid};
+    SMMUEventInfo event = {.type = SMMU_EVT_NONE,
+                           .sid = sid,
+                           .inval_ste_allowed = false};
     SMMUPTWEventInfo ptw_info = {};
     SMMUTranslationStatus status;
     SMMUState *bs = ARM_SMMU(s);
@@ -796,16 +802,13 @@ static void smmuv3_notify_iova(IOMMUMemoryRegion *mr,
                                dma_addr_t iova)
 {
     SMMUDevice *sdev = container_of(mr, SMMUDevice, iommu);
-    SMMUEventInfo event = {};
+    SMMUEventInfo event = {.inval_ste_allowed = true};
     SMMUTransTableInfo *tt;
     SMMUTransCfg *cfg;
     IOMMUTLBEntry entry;
 
     cfg = smmuv3_get_config(sdev, &event);
     if (!cfg) {
-        qemu_log_mask(LOG_GUEST_ERROR,
-                      "%s error decoding the configuration for iommu mr=%s\n",
-                      __func__, mr->parent_obj.name);
         return;
     }
 
-- 
2.20.1