vfio/common: remove spurious tpm-crb-cmd misalignment warning

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>
Link: https://lore.kernel.org/r/20220506132510.1847942-3-eric.auger@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 26 insertions, 1 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 6065834717..cfcb71974a 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;
     }