[PATCH v4] vfio/common: remove spurious tpm-crb-cmd misalignment warning

[Eric Auger]

The CRB command buffer currently is a RAM MemoryRegion and given
its base address alignment, it causes an error report on
vfio_listener_region_add(). This region could have been a RAM device
region, easing the detection of such safe situation but this option
was not well received. So let's add a helper function that uses the
memory region owner type to detect the situation is safe wrt
the assignment. Other device types can be checked here if such kind
of problem occurs again.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

---

v3 -> v4:
- rebase on top of qemu_real_host_page_size() and
  qemu_real_host_page_size(). Print the size and make the message
  consistent
- Added Stefan's A-b and Connie R-b (despite the changes)
---
 hw/vfio/common.c     | 27 ++++++++++++++++++++++++++-
 hw/vfio/trace-events |  1 +
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 2b1f78fdfa..f6b9bb6d71 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -40,6 +40,7 @@
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/migration.h"
+#include "sysemu/tpm.h"
 
 VFIOGroupList vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
@@ -861,6 +862,22 @@ static void 
vfio_unregister_ram_discard_listener(VFIOContainer *container,
     g_free(vrdl);
 }
 
+static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
+{
+    MemoryRegion *mr = section->mr;
+
+    if (!TPM_IS_CRB(mr->owner)) {
+        return false;
+    }
+
+    /* this is a known safe misaligned region, just trace for debug purpose */
+    trace_vfio_known_safe_misalignment(memory_region_name(mr),
+                                       section->offset_within_address_space,
+                                       section->offset_within_region,
+                                       qemu_real_host_page_size());
+    return true;
+}
+
 static void vfio_listener_region_add(MemoryListener *listener,
                                      MemoryRegionSection *section)
 {
@@ -884,7 +901,15 @@ 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 (!vfio_known_safe_misalignment(section)) {
+            error_report("%s received unaligned region %s iova=0x%"PRIx64
+                         " offset_within_region=0x%"PRIx64
+                         " qemu_real_host_page_size=0x%"PRIxPTR,
+                         __func__, memory_region_name(section->mr),
+                         section->offset_within_address_space,
+                         section->offset_within_region,
+                         qemu_real_host_page_size());
+        }
         return;
     }
 
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 0ef1b5f4a6..582882db91 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_known_safe_misalignment(const char *name, uint64_t iova, uint64_t 
offset_within_region, uintptr_t page_size) "Region \"%s\" iova=0x%"PRIx64" 
offset_within_region=0x%"PRIx64" qemu_real_host_page_size=0x%"PRIxPTR ": 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
-- 
2.34.1