Re: [PATCH v2 2/2] hw/vfio/common: Silence ram device offset alignment error traces

[Stefan Berger]

On 1/19/22 15:13, Alex Williamson wrote:

On Tue, 18 Jan 2022 16:33:06 +0100
Eric Auger <eric.au...@redhat.com> wrote:

Failing to DMA MAP a ram_device should not cause an error message.
This is currently happening with the TPM CRB command region and
this is causing confusion.

We may want to keep the trace for debug purpose though.

Signed-off-by: Eric Auger <eric.au...@redhat.com>
Tested-by: Stefan Berger <stef...@linux.ibm.com>
---
  hw/vfio/common.c     | 15 ++++++++++++++-
  hw/vfio/trace-events |  1 +
  2 files changed, 15 insertions(+), 1 deletion(-)

Thanks!  Looks good to me.

Stefan, I can provide an ack here if you want to send a pull request
for both or likewise I can send a pull request with your ack on the
previous patch.  I suppose the patches themselves are technically
independent if you want to split them.  Whichever you prefer.

Acked-by: Alex Williamson <alex.william...@redhat.com>

If you want to send the PR, please go ahead.

   Stefan

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 080046e3f5..9caa560b07 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -884,7 +884,20 @@ static void vfio_listener_region_add(MemoryListener 
*listener,
      if (unlikely((section->offset_within_address_space &
                    ~qemu_real_host_page_mask) !=
                   (section->offset_within_region & 
~qemu_real_host_page_mask))) {
-        error_report("%s received unaligned region", __func__);
+        if (memory_region_is_ram_device(section->mr)) { /* just debug purpose 
*/
+            trace_vfio_listener_region_add_bad_offset_alignment(
+                memory_region_name(section->mr),
+                section->offset_within_address_space,
+                section->offset_within_region, qemu_real_host_page_size);
+        } else { /* error case we don't want to be fatal */
+            error_report("%s received unaligned region %s iova=0x%"PRIx64
+                         " offset_within_region=0x%"PRIx64
+                         " qemu_real_host_page_mask=0x%"PRIx64,
+                         __func__, memory_region_name(section->mr),
+                         section->offset_within_address_space,
+                         section->offset_within_region,
+                         qemu_real_host_page_mask);
+        }
          return;
      }

diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events

index 0ef1b5f4a6..ccd9d7610d 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -100,6 +100,7 @@ vfio_listener_region_add_skip(uint64_t start, uint64_t end) 
"SKIPPING region_add
  vfio_spapr_group_attach(int groupfd, int tablefd) "Attached groupfd %d to liobn fd 
%d"
  vfio_listener_region_add_iommu(uint64_t start, uint64_t end) "region_add [iommu] 
0x%"PRIx64" - 0x%"PRIx64
  vfio_listener_region_add_ram(uint64_t iova_start, uint64_t iova_end, void *vaddr) "region_add [ram] 
0x%"PRIx64" - 0x%"PRIx64" [%p]"
+vfio_listener_region_add_bad_offset_alignment(const char *name, uint64_t iova, uint64_t offset_within_region, uint64_t 
page_size) "Region \"%s\" @0x%"PRIx64", offset_within_region=0x%"PRIx64", 
qemu_real_host_page_mask=0x%"PRIx64 " cannot be mapped for DMA"
  vfio_listener_region_add_no_dma_map(const char *name, uint64_t iova, uint64_t size, uint64_t page_size) "Region 
\"%s\" 0x%"PRIx64" size=0x%"PRIx64" is not aligned to 0x%"PRIx64" and cannot be mapped 
for DMA"
  vfio_listener_region_del_skip(uint64_t start, uint64_t end) "SKIPPING region_del 
0x%"PRIx64" - 0x%"PRIx64
  vfio_listener_region_del(uint64_t start, uint64_t end) "region_del 0x%"PRIx64" - 
0x%"PRIx64