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  13. Jul 10, 2020
    • Markus Armbruster's avatar
      error: Eliminate error_propagate() with Coccinelle, part 1 · 668f62ec
      Markus Armbruster authored
      
      When all we do with an Error we receive into a local variable is
      propagating to somewhere else, we can just as well receive it there
      right away.  Convert
      
          if (!foo(..., &err)) {
              ...
              error_propagate(errp, err);
              ...
              return ...
          }
      
      to
      
          if (!foo(..., errp)) {
              ...
              ...
              return ...
          }
      
      where nothing else needs @err.  Coccinelle script:
      
          @rule1 forall@
          identifier fun, err, errp, lbl;
          expression list args, args2;
          binary operator op;
          constant c1, c2;
          symbol false;
          @@
               if (
          (
          -        fun(args, &err, args2)
          +        fun(args, errp, args2)
          |
          -        !fun(args, &err, args2)
          +        !fun(args, errp, args2)
          |
          -        fun(args, &err, args2) op c1
          +        fun(args, errp, args2) op c1
          )
                  )
               {
                   ... when != err
                       when != lbl:
                       when strict
          -        error_propagate(errp, err);
                   ... when != err
          (
                   return;
          |
                   return c2;
          |
                   return false;
          )
               }
      
          @rule2 forall@
          identifier fun, err, errp, lbl;
          expression list args, args2;
          expression var;
          binary operator op;
          constant c1, c2;
          symbol false;
          @@
          -    var = fun(args, &err, args2);
          +    var = fun(args, errp, args2);
               ... when != err
               if (
          (
                   var
          |
                   !var
          |
                   var op c1
          )
                  )
               {
                   ... when != err
                       when != lbl:
                       when strict
          -        error_propagate(errp, err);
                   ... when != err
          (
                   return;
          |
                   return c2;
          |
                   return false;
          |
                   return var;
          )
               }
      
          @depends on rule1 || rule2@
          identifier err;
          @@
          -    Error *err = NULL;
               ... when != err
      
      Not exactly elegant, I'm afraid.
      
      The "when != lbl:" is necessary to avoid transforming
      
               if (fun(args, &err)) {
                   goto out
               }
               ...
           out:
               error_propagate(errp, err);
      
      even though other paths to label out still need the error_propagate().
      For an actual example, see sclp_realize().
      
      Without the "when strict", Coccinelle transforms vfio_msix_setup(),
      incorrectly.  I don't know what exactly "when strict" does, only that
      it helps here.
      
      The match of return is narrower than what I want, but I can't figure
      out how to express "return where the operand doesn't use @err".  For
      an example where it's too narrow, see vfio_intx_enable().
      
      Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
      confused by ARMSSE being used both as typedef and function-like macro
      there.  Converted manually.
      
      Line breaks tidied up manually.  One nested declaration of @local_err
      deleted manually.  Preexisting unwanted blank line dropped in
      hw/riscv/sifive_e.c.
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Message-Id: <20200707160613.848843-35-armbru@redhat.com>
      668f62ec
    • Markus Armbruster's avatar
      error: Avoid unnecessary error_propagate() after error_setg() · dcfe4805
      Markus Armbruster authored
      
      Replace
      
          error_setg(&err, ...);
          error_propagate(errp, err);
      
      by
      
          error_setg(errp, ...);
      
      Related pattern:
      
          if (...) {
              error_setg(&err, ...);
              goto out;
          }
          ...
       out:
          error_propagate(errp, err);
          return;
      
      When all paths to label out are that way, replace by
      
          if (...) {
              error_setg(errp, ...);
              return;
          }
      
      and delete the label along with the error_propagate().
      
      When we have at most one other path that actually needs to propagate,
      and maybe one at the end that where propagation is unnecessary, e.g.
      
          foo(..., &err);
          if (err) {
              goto out;
          }
          ...
          bar(..., &err);
       out:
          error_propagate(errp, err);
          return;
      
      move the error_propagate() to where it's needed, like
      
          if (...) {
              foo(..., &err);
              error_propagate(errp, err);
              return;
          }
          ...
          bar(..., errp);
          return;
      
      and transform the error_setg() as above.
      
      In some places, the transformation results in obviously unnecessary
      error_propagate().  The next few commits will eliminate them.
      
      Bonus: the elimination of gotos will make later patches in this series
      easier to review.
      
      Candidates for conversion tracked down with this Coccinelle script:
      
          @@
          identifier err, errp;
          expression list args;
          @@
          -    error_setg(&err, args);
          +    error_setg(errp, args);
               ... when != err
               error_propagate(errp, err);
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Message-Id: <20200707160613.848843-34-armbru@redhat.com>
      dcfe4805
    • Markus Armbruster's avatar
      qom: Put name parameter before value / visitor parameter · 5325cc34
      Markus Armbruster authored
      
      The object_property_set_FOO() setters take property name and value in
      an unusual order:
      
          void object_property_set_FOO(Object *obj, FOO_TYPE value,
                                       const char *name, Error **errp)
      
      Having to pass value before name feels grating.  Swap them.
      
      Same for object_property_set(), object_property_get(), and
      object_property_parse().
      
      Convert callers with this Coccinelle script:
      
          @@
          identifier fun = {
              object_property_get, object_property_parse, object_property_set_str,
              object_property_set_link, object_property_set_bool,
              object_property_set_int, object_property_set_uint, object_property_set,
              object_property_set_qobject
          };
          expression obj, v, name, errp;
          @@
          -    fun(obj, v, name, errp)
          +    fun(obj, name, v, errp)
      
      Chokes on hw/arm/musicpal.c's lcd_refresh() with the unhelpful error
      message "no position information".  Convert that one manually.
      
      Fails to convert hw/arm/armsse.c, because Coccinelle gets confused by
      ARMSSE being used both as typedef and function-like macro there.
      Convert manually.
      
      Fails to convert hw/rx/rx-gdbsim.c, because Coccinelle gets confused
      by RXCPU being used both as typedef and function-like macro there.
      Convert manually.  The other files using RXCPU that way don't need
      conversion.
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
      Message-Id: <20200707160613.848843-27-armbru@redhat.com>
      [Straightforwad conflict with commit 2336172d "audio: set default
      value for pcspk.iobase property" resolved]
      5325cc34
    • Markus Armbruster's avatar
      qapi: Use returned bool to check for failure, manual part · 14217038
      Markus Armbruster authored
      
      The previous commit used Coccinelle to convert from checking the Error
      object to checking the return value.  Convert a few more manually.
      Also tweak control flow in places to conform to the conventional "if
      error bail out" pattern.
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
      Message-Id: <20200707160613.848843-20-armbru@redhat.com>
      14217038
    • Markus Armbruster's avatar
      qapi: Use returned bool to check for failure, Coccinelle part · 62a35aaa
      Markus Armbruster authored
      
      The previous commit enables conversion of
      
          visit_foo(..., &err);
          if (err) {
              ...
          }
      
      to
      
          if (!visit_foo(..., errp)) {
              ...
          }
      
      for visitor functions that now return true / false on success / error.
      Coccinelle script:
      
          @@
          identifier fun =~ "check_list|input_type_enum|lv_start_struct|lv_type_bool|lv_type_int64|lv_type_str|lv_type_uint64|output_type_enum|parse_type_bool|parse_type_int64|parse_type_null|parse_type_number|parse_type_size|parse_type_str|parse_type_uint64|print_type_bool|print_type_int64|print_type_null|print_type_number|print_type_size|print_type_str|print_type_uint64|qapi_clone_start_alternate|qapi_clone_start_list|qapi_clone_start_struct|qapi_clone_type_bool|qapi_clone_type_int64|qapi_clone_type_null|qapi_clone_type_number|qapi_clone_type_str|qapi_clone_type_uint64|qapi_dealloc_start_list|qapi_dealloc_start_struct|qapi_dealloc_type_anything|qapi_dealloc_type_bool|qapi_dealloc_type_int64|qapi_dealloc_type_null|qapi_dealloc_type_number|qapi_dealloc_type_str|qapi_dealloc_type_uint64|qobject_input_check_list|qobject_input_check_struct|qobject_input_start_alternate|qobject_input_start_list|qobject_input_start_struct|qobject_input_type_any|qobject_input_type_bool|qobject_input_type_bool_keyval|qobject_input_type_int64|qobject_input_type_int64_keyval|qobject_input_type_null|qobject_input_type_number|qobject_input_type_number_keyval|qobject_input_type_size_keyval|qobject_input_type_str|qobject_input_type_str_keyval|qobject_input_type_uint64|qobject_input_type_uint64_keyval|qobject_output_start_list|qobject_output_start_struct|qobject_output_type_any|qobject_output_type_bool|qobject_output_type_int64|qobject_output_type_null|qobject_output_type_number|qobject_output_type_str|qobject_output_type_uint64|start_list|visit_check_list|visit_check_struct|visit_start_alternate|visit_start_list|visit_start_struct|visit_type_.*";
          expression list args;
          typedef Error;
          Error *err;
          @@
          -    fun(args, &err);
          -    if (err)
          +    if (!fun(args, &err))
               {
                   ...
               }
      
      A few line breaks tidied up manually.
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
      Message-Id: <20200707160613.848843-19-armbru@redhat.com>
      62a35aaa
  14. May 27, 2020
  15. May 15, 2020
    • Markus Armbruster's avatar
      qdev: Unrealize must not fail · b69c3c21
      Markus Armbruster authored
      
      Devices may have component devices and buses.
      
      Device realization may fail.  Realization is recursive: a device's
      realize() method realizes its components, and device_set_realized()
      realizes its buses (which should in turn realize the devices on that
      bus, except bus_set_realized() doesn't implement that, yet).
      
      When realization of a component or bus fails, we need to roll back:
      unrealize everything we realized so far.  If any of these unrealizes
      failed, the device would be left in an inconsistent state.  Must not
      happen.
      
      device_set_realized() lets it happen: it ignores errors in the roll
      back code starting at label child_realize_fail.
      
      Since realization is recursive, unrealization must be recursive, too.
      But how could a partly failed unrealize be rolled back?  We'd have to
      re-realize, which can fail.  This design is fundamentally broken.
      
      device_set_realized() does not roll back at all.  Instead, it keeps
      unrealizing, ignoring further errors.
      
      It can screw up even for a device with no buses: if the lone
      dc->unrealize() fails, it still unregisters vmstate, and calls
      listeners' unrealize() callback.
      
      bus_set_realized() does not roll back either.  Instead, it stops
      unrealizing.
      
      Fortunately, no unrealize method can fail, as we'll see below.
      
      To fix the design error, drop parameter @errp from all the unrealize
      methods.
      
      Any unrealize method that uses @errp now needs an update.  This leads
      us to unrealize() methods that can fail.  Merely passing it to another
      unrealize method cannot cause failure, though.  Here are the ones that
      do other things with @errp:
      
      * virtio_serial_device_unrealize()
      
        Fails when qbus_set_hotplug_handler() fails, but still does all the
        other work.  On failure, the device would stay realized with its
        resources completely gone.  Oops.  Can't happen, because
        qbus_set_hotplug_handler() can't actually fail here.  Pass
        &error_abort to qbus_set_hotplug_handler() instead.
      
      * hw/ppc/spapr_drc.c's unrealize()
      
        Fails when object_property_del() fails, but all the other work is
        already done.  On failure, the device would stay realized with its
        vmstate registration gone.  Oops.  Can't happen, because
        object_property_del() can't actually fail here.  Pass &error_abort
        to object_property_del() instead.
      
      * spapr_phb_unrealize()
      
        Fails and bails out when remove_drcs() fails, but other work is
        already done.  On failure, the device would stay realized with some
        of its resources gone.  Oops.  remove_drcs() fails only when
        chassis_from_bus()'s object_property_get_uint() fails, and it can't
        here.  Pass &error_abort to remove_drcs() instead.
      
      Therefore, no unrealize method can fail before this patch.
      
      device_set_realized()'s recursive unrealization via bus uses
      object_property_set_bool().  Can't drop @errp there, so pass
      &error_abort.
      
      We similarly unrealize with object_property_set_bool() elsewhere,
      always ignoring errors.  Pass &error_abort instead.
      
      Several unrealize methods no longer handle errors from other unrealize
      methods: virtio_9p_device_unrealize(),
      virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
      Much of the deleted error handling looks wrong anyway.
      
      One unrealize methods no longer ignore such errors:
      usb_ehci_pci_exit().
      
      Several realize methods no longer ignore errors when rolling back:
      v9fs_device_realize_common(), pci_qdev_unrealize(),
      spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
      virtio_device_realize().
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
      Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Message-Id: <20200505152926.18877-17-armbru@redhat.com>
      b69c3c21
    • Markus Armbruster's avatar
      qom: Drop parameter @errp of object_property_add() & friends · d2623129
      Markus Armbruster authored
      
      The only way object_property_add() can fail is when a property with
      the same name already exists.  Since our property names are all
      hardcoded, failure is a programming error, and the appropriate way to
      handle it is passing &error_abort.
      
      Same for its variants, except for object_property_add_child(), which
      additionally fails when the child already has a parent.  Parentage is
      also under program control, so this is a programming error, too.
      
      We have a bit over 500 callers.  Almost half of them pass
      &error_abort, slightly fewer ignore errors, one test case handles
      errors, and the remaining few callers pass them to their own callers.
      
      The previous few commits demonstrated once again that ignoring
      programming errors is a bad idea.
      
      Of the few ones that pass on errors, several violate the Error API.
      The Error ** argument must be NULL, &error_abort, &error_fatal, or a
      pointer to a variable containing NULL.  Passing an argument of the
      latter kind twice without clearing it in between is wrong: if the
      first call sets an error, it no longer points to NULL for the second
      call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
      sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
      are wrong that way.
      
      When the one appropriate choice of argument is &error_abort, letting
      users pick the argument is a bad idea.
      
      Drop parameter @errp and assert the preconditions instead.
      
      There's one exception to "duplicate property name is a programming
      error": the way object_property_add() implements the magic (and
      undocumented) "automatic arrayification".  Don't drop @errp there.
      Instead, rename object_property_add() to object_property_try_add(),
      and add the obvious wrapper object_property_add().
      
      Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Message-Id: <20200505152926.18877-15-armbru@redhat.com>
      [Two semantic rebase conflicts resolved]
      d2623129
  16. May 04, 2020
  17. Feb 20, 2020
    • Shivaprasad G Bhat's avatar
      spapr: Add NVDIMM device support · ee3a71e3
      Shivaprasad G Bhat authored
      
      Add support for NVDIMM devices for sPAPR. Piggyback on existing nvdimm
      device interface in QEMU to support virtual NVDIMM devices for Power.
      Create the required DT entries for the device (some entries have
      dummy values right now).
      
      The patch creates the required DT node and sends a hotplug
      interrupt to the guest. Guest is expected to undertake the normal
      DR resource add path in response and start issuing PAPR SCM hcalls.
      
      The device support is verified based on the machine version unlike x86.
      
      This is how it can be used ..
      Ex :
      For coldplug, the device to be added in qemu command line as shown below
      -object memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/tmp/nvdimm0,share=yes,size=1073872896
      -device nvdimm,label-size=128k,uuid=75a3cdd7-6a2f-4791-8d15-fe0a920e8e9e,memdev=memnvdimm0,id=nvdimm0,slot=0
      
      For hotplug, the device to be added from monitor as below
      object_add memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/tmp/nvdimm0,share=yes,size=1073872896
      device_add nvdimm,label-size=128k,uuid=75a3cdd7-6a2f-4791-8d15-fe0a920e8e9e,memdev=memnvdimm0,id=nvdimm0,slot=0
      
      Signed-off-by: default avatarShivaprasad G Bhat <sbhat@linux.ibm.com>
      Signed-off-by: default avatarBharata B Rao <bharata@linux.ibm.com>
                     [Early implementation]
      Message-Id: <158131058078.2897.12767731856697459923.stgit@lep8c.aus.stglabs.ibm.com>
      Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      ee3a71e3
    • Shivaprasad G Bhat's avatar
      nvdimm: add uuid property to nvdimm · 6c5627bb
      Shivaprasad G Bhat authored
      
      For ppc64, PAPR requires the nvdimm device to have UUID property
      set in the device tree. Add an option to get it from the user.
      
      Signed-off-by: default avatarShivaprasad G Bhat <sbhat@linux.ibm.com>
      Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Reviewed-by: default avatarIgor Mammedov <imammedo@redhat.com>
      Message-Id: <158131056931.2897.14057087440721445976.stgit@lep8c.aus.stglabs.ibm.com>
      Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      6c5627bb
  18. Jan 24, 2020
  19. Dec 18, 2019
  20. Oct 22, 2019
  21. Oct 15, 2019
  22. Sep 03, 2019
  23. Aug 16, 2019
  24. Jul 29, 2019
  25. Jun 12, 2019
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