[Qemu-devel] [PATCH v2 4/4] pc-dimm: assign and verify the "addr" property during pre_plug

[David Hildenbrand <david@redhat.com>]

We can assign and verify the slot before realizing and trying to plug.
reading/writing the address property should never fail, so let's reduce
error handling a bit by using &error_abort. Getting access to the memory
region now might however fail. So forward errors from
get_memory_region() properly.

Keep tracing the assigned address for now in the plug code, as that's the
point we are sure plugging succeeded and the address willa ctually be
used.

As all memory devices should use the alignment of the underlying memory
region for guest physical address asignment, do detection of the
alignment in pc_dimm_pre_plug(), but allow pc.c to overwrite the
alignment for compatibility handling.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/i386/pc.c             | 16 ++++--------
 hw/mem/pc-dimm.c         | 53 +++++++++++++++++++++++-----------------
 hw/ppc/spapr.c           |  7 +++---
 include/hw/mem/pc-dimm.h |  6 ++---
 4 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 934b7155b1..16e4b5baff 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1678,7 +1678,9 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
                                Error **errp)
 {
     const PCMachineState *pcms = PC_MACHINE(hotplug_dev);
+    const PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
     const bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
+    const uint64_t compat_align = TARGET_PAGE_SIZE;
 
     /*
      * When -no-acpi is used with Q35 machine type, no ACPI is built,
@@ -1696,7 +1698,8 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
         return;
     }
 
-    pc_dimm_pre_plug(dev, MACHINE(hotplug_dev), errp);
+    pc_dimm_pre_plug(dev, MACHINE(hotplug_dev),
+                     pcmc->enforce_aligned_dimm ? NULL : &compat_align, errp);
 }
 
 static void pc_memory_plug(HotplugHandler *hotplug_dev,
@@ -1705,18 +1708,9 @@ static void pc_memory_plug(HotplugHandler *hotplug_dev,
     HotplugHandlerClass *hhc;
     Error *local_err = NULL;
     PCMachineState *pcms = PC_MACHINE(hotplug_dev);
-    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
-    PCDIMMDevice *dimm = PC_DIMM(dev);
-    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
-    MemoryRegion *mr = ddc->get_memory_region(dimm, &error_abort);
-    uint64_t align = TARGET_PAGE_SIZE;
     bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
 
-    if (pcmc->enforce_aligned_dimm) {
-        align = memory_region_get_alignment(mr);
-    }
-
-    pc_dimm_plug(dev, MACHINE(pcms), align, &local_err);
+    pc_dimm_plug(dev, MACHINE(pcms), &local_err);
     if (local_err) {
         goto out;
     }
diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index e56c4daef2..8e2e8549dc 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -29,9 +29,14 @@
 
 static int pc_dimm_get_free_slot(const int *hint, int max_slots, Error **errp);
 
-void pc_dimm_pre_plug(DeviceState *dev, MachineState *machine, Error **errp)
+void pc_dimm_pre_plug(DeviceState *dev, MachineState *machine,
+                      const uint64_t *compat_align, Error **errp)
 {
+    PCDIMMDevice *dimm = PC_DIMM(dev);
+    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
     Error *local_err = NULL;
+    MemoryRegion *mr;
+    uint64_t addr, align;
     int slot;
 
     slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP,
@@ -43,44 +48,46 @@ void pc_dimm_pre_plug(DeviceState *dev, MachineState *machine, Error **errp)
     }
     object_property_set_int(OBJECT(dev), slot, PC_DIMM_SLOT_PROP, &error_abort);
     trace_mhp_pc_dimm_assigned_slot(slot);
+
+    mr = ddc->get_memory_region(dimm, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (compat_align) {
+        align = *compat_align;
+    } else {
+        align = memory_region_get_alignment(mr);
+    }
+
+    addr = object_property_get_uint(OBJECT(dev), PC_DIMM_ADDR_PROP,
+                                    &error_abort);
+    addr = memory_device_get_free_addr(machine, !addr ? NULL : &addr, align,
+                                       memory_region_size(mr), &local_err);
+    if (local_err) {
+        goto out;
+    }
+    object_property_set_uint(OBJECT(dev), addr, PC_DIMM_ADDR_PROP,
+                             &error_abort);
 out:
     error_propagate(errp, local_err);
 }
 
-void pc_dimm_plug(DeviceState *dev, MachineState *machine, uint64_t align,
-                  Error **errp)
+void pc_dimm_plug(DeviceState *dev, MachineState *machine, Error **errp)
 {
     PCDIMMDevice *dimm = PC_DIMM(dev);
     PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
     MemoryRegion *vmstate_mr = ddc->get_vmstate_memory_region(dimm,
                                                               &error_abort);
     MemoryRegion *mr = ddc->get_memory_region(dimm, &error_abort);
-    Error *local_err = NULL;
     uint64_t addr;
 
-    addr = object_property_get_uint(OBJECT(dimm),
-                                    PC_DIMM_ADDR_PROP, &local_err);
-    if (local_err) {
-        goto out;
-    }
-
-    addr = memory_device_get_free_addr(machine, !addr ? NULL : &addr, align,
-                                       memory_region_size(mr), &local_err);
-    if (local_err) {
-        goto out;
-    }
-
-    object_property_set_uint(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
-    if (local_err) {
-        goto out;
-    }
+    addr = object_property_get_uint(OBJECT(dev), PC_DIMM_ADDR_PROP,
+                                    &error_abort);
     trace_mhp_pc_dimm_assigned_address(addr);
 
     memory_device_plug_region(machine, mr, addr);
     vmstate_register_ram(vmstate_mr, dev);
-
-out:
-    error_propagate(errp, local_err);
 }
 
 void pc_dimm_unplug(DeviceState *dev, MachineState *machine)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index bf012235b6..33543c6373 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3150,13 +3150,12 @@ static void spapr_memory_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
     PCDIMMDevice *dimm = PC_DIMM(dev);
     PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
     MemoryRegion *mr = ddc->get_memory_region(dimm, &error_abort);
-    uint64_t align, size, addr;
+    uint64_t size, addr;
     uint32_t node;
 
-    align = memory_region_get_alignment(mr);
     size = memory_region_size(mr);
 
-    pc_dimm_plug(dev, MACHINE(ms), align, &local_err);
+    pc_dimm_plug(dev, MACHINE(ms), &local_err);
     if (local_err) {
         goto out;
     }
@@ -3223,7 +3222,7 @@ static void spapr_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
         return;
     }
 
-    pc_dimm_pre_plug(dev, MACHINE(hotplug_dev), errp);
+    pc_dimm_pre_plug(dev, MACHINE(hotplug_dev), NULL, errp);
 }
 
 struct sPAPRDIMMState {
diff --git a/include/hw/mem/pc-dimm.h b/include/hw/mem/pc-dimm.h
index 7b120416d1..6457b2a25f 100644
--- a/include/hw/mem/pc-dimm.h
+++ b/include/hw/mem/pc-dimm.h
@@ -79,8 +79,8 @@ typedef struct PCDIMMDeviceClass {
                                                Error **errp);
 } PCDIMMDeviceClass;
 
-void pc_dimm_pre_plug(DeviceState *dev, MachineState *machine, Error **errp);
-void pc_dimm_plug(DeviceState *dev, MachineState *machine, uint64_t align,
-                  Error **errp);
+void pc_dimm_pre_plug(DeviceState *dev, MachineState *machine,
+                      const uint64_t *compat_align, Error **errp);
+void pc_dimm_plug(DeviceState *dev, MachineState *machine, Error **errp);
 void pc_dimm_unplug(DeviceState *dev, MachineState *machine);
 #endif
-- 
2.17.1