@@ -2855,6 +2855,11 @@ static void spapr_set_modern_hotplug_events(Object *obj, bool value,
spapr->use_hotplug_event_source = value;
}
+static bool spapr_get_msix_emulation(Object *obj, Error **errp)
+{
+ return true;
+}
+
static char *spapr_get_resize_hpt(Object *obj, Error **errp)
{
sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
@@ -2936,6 +2941,8 @@ static void spapr_instance_init(Object *obj)
object_property_set_description(obj, "vsmt",
"Virtual SMT: KVM behaves as if this were"
" the host's SMT mode", &error_abort);
+ object_property_add_bool(obj, "vfio-no-msix-emulation",
+ spapr_get_msix_emulation, NULL, NULL);
}
static void spapr_machine_finalizefn(Object *obj)
@@ -1581,6 +1581,19 @@ static int vfio_msix_setup(VFIOPCIDevice *vdev, int pos, Error **errp)
*/
memory_region_set_enabled(&vdev->pdev.msix_pba_mmio, false);
+ /*
+ * The emulated machine may provide a paravirt interface for MSIX setup
+ * so it is not strictly necessary to emulate MSIX here. This becomes
+ * helpful when frequently accessed MMIO registers are located in
+ * subpages adjacent to the MSIX table but the MSIX data containing page
+ * cannot be mapped because of a host page size bigger than the MSIX table
+ * alignment.
+ */
+ if (object_property_get_bool(OBJECT(qdev_get_machine()),
+ "vfio-no-msix-emulation", NULL)) {
+ memory_region_set_enabled(&vdev->pdev.msix_table_mmio, false);
+ }
+
return 0;
}