From: Eric Auger <eric.auger@redhat.com>

The current error messages in virtio_iommu_set_page_size_mask()
sound quite similar for different situations and miss the IOMMU
memory region that causes the issue.

Clarify them and rework the comment.

Also remove the trace when the new page_size_mask is not applied as
the current frozen granule is kept. This message is rather confusing
for the end user and anyway the current granule would have been used
by the driver.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20230705165118.28194-3-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 hw/virtio/virtio-iommu.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 8d0c5e3f32..201127c488 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -1101,29 +1101,24 @@ static int virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
                                           new_mask);
 
     if ((cur_mask & new_mask) == 0) {
-        error_setg(errp, "virtio-iommu page mask 0x%"PRIx64
-                   " is incompatible with mask 0x%"PRIx64, cur_mask, new_mask);
+        error_setg(errp, "virtio-iommu %s reports a page size mask 0x%"PRIx64
+                   " incompatible with currently supported mask 0x%"PRIx64,
+                   mr->parent_obj.name, new_mask, cur_mask);
         return -1;
     }
 
     /*
      * Once the granule is frozen we can't change the mask anymore. If by
      * chance the hotplugged device supports the same granule, we can still
-     * accept it. Having a different masks is possible but the guest will use
-     * sub-optimal block sizes, so warn about it.
+     * accept it.
      */
     if (s->granule_frozen) {
-        int new_granule = ctz64(new_mask);
         int cur_granule = ctz64(cur_mask);
 
-        if (new_granule != cur_granule) {
-            error_setg(errp, "virtio-iommu page mask 0x%"PRIx64
-                       " is incompatible with mask 0x%"PRIx64, cur_mask,
-                       new_mask);
+        if (!(BIT(cur_granule) & new_mask)) {
+            error_setg(errp, "virtio-iommu %s does not support frozen granule 0x%llx",
+                       mr->parent_obj.name, BIT_ULL(cur_granule));
             return -1;
-        } else if (new_mask != cur_mask) {
-            warn_report("virtio-iommu page mask 0x%"PRIx64
-                        " does not match 0x%"PRIx64, cur_mask, new_mask);
         }
         return 0;
     }
-- 
MST