spapr_vio/spapr_iommu: Move VIO bypass where it belongs

Instead of tweaking a TCE table device by adding there a bypass flag,
let's add an alias to RAM and IOMMU memory region, and enable/disable
those according to the selected bypass mode.
This way IOMMU memory region can have size of the actual window rather
than ram_size which is essential for upcoming DDW support.

This moves bypass logic to VIO layer and keeps @bypass flag in TCE table
for migration compatibility only. This replaces spapr_tce_set_bypass()
calls with explicit assignment to avoid confusion as the function could
do something more that just syncing the @bypass flag.

This adds a pointer to VIO device into the sPAPRTCETable struct to provide
the sPAPRTCETable device a way to update bypass mode for the VIO device.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 26 insertions, 2 deletions

diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index 032ee1a5f1..245cdd70d8 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -322,6 +322,18 @@ static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
     free_crq(dev);
 }
 
+void spapr_vio_set_bypass(VIOsPAPRDevice *dev, bool bypass)
+{
+    if (!dev->tcet) {
+        return;
+    }
+
+    memory_region_set_enabled(&dev->mrbypass, bypass);
+    memory_region_set_enabled(spapr_tce_get_iommu(dev->tcet), !bypass);
+
+    dev->tcet->bypass = bypass;
+}
+
 static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                                 uint32_t token,
                                 uint32_t nargs, target_ulong args,
@@ -348,7 +360,7 @@ static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPREnvironment *spapr,
         return;
     }
 
-    spapr_tce_set_bypass(dev->tcet, !!enable);
+    spapr_vio_set_bypass(dev, !!enable);
 
     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 }
@@ -407,6 +419,7 @@ static void spapr_vio_busdev_reset(DeviceState *qdev)
 
     dev->signal_state = 0;
 
+    spapr_vio_set_bypass(dev, false);
     if (pc->reset) {
         pc->reset(dev);
     }
@@ -456,12 +469,23 @@ static int spapr_vio_busdev_init(DeviceState *qdev)
 
     if (pc->rtce_window_size) {
         uint32_t liobn = SPAPR_VIO_BASE_LIOBN | dev->reg;
+
+        memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
+                           ram_size);
+        memory_region_init_alias(&dev->mrbypass, OBJECT(dev),
+                                 "iommu-spapr-bypass", get_system_memory(),
+                                 0, ram_size);
+        memory_region_add_subregion_overlap(&dev->mrroot, 0, &dev->mrbypass, 1);
+        address_space_init(&dev->as, &dev->mrroot, qdev->id);
+
         dev->tcet = spapr_tce_new_table(qdev, liobn,
                                         0,
                                         SPAPR_TCE_PAGE_SHIFT,
                                         pc->rtce_window_size >>
                                         SPAPR_TCE_PAGE_SHIFT, false);
-        address_space_init(&dev->as, spapr_tce_get_iommu(dev->tcet), qdev->id);
+        dev->tcet->vdev = dev;
+        memory_region_add_subregion_overlap(&dev->mrroot, 0,
+                                            spapr_tce_get_iommu(dev->tcet), 2);
     }
 
     return pc->init(dev);