[Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Markus Armbruster]

This reverts commit 7426aa72c36c908a7d0eae3e38568bb0a70de479.

The commit goes into a sensible direction, but it violates qdev design
assumptions.  Symptom: "info qtree" crashes for all boards including
the device (akita, borzoi, spitz, terrier, tosa, axis-dev88).

Peter Crosthwaite is working on a fix, but it's not trivial.  Revert
the flawed patch for now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
---
 hw/block/nand.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/block/nand.c b/hw/block/nand.c
index a871ce0..a0232d1 100644
--- a/hw/block/nand.c
+++ b/hw/block/nand.c
@@ -21,7 +21,7 @@
 # include "hw/hw.h"
 # include "hw/block/flash.h"
 # include "sysemu/blockdev.h"
-#include "hw/qdev.h"
+# include "hw/sysbus.h"
 #include "qemu/error-report.h"
 
 # define NAND_CMD_READ0		0x00
@@ -54,8 +54,7 @@
 
 typedef struct NANDFlashState NANDFlashState;
 struct NANDFlashState {
-    DeviceState parent_obj;
-
+    SysBusDevice busdev;
     uint8_t manf_id, chip_id;
     uint8_t buswidth; /* in BYTES */
     int size, pages;
@@ -441,7 +440,7 @@ static void nand_class_init(ObjectClass *klass, void *data)
 
 static const TypeInfo nand_info = {
     .name          = TYPE_NAND,
-    .parent        = TYPE_DEVICE,
+    .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(NANDFlashState),
     .class_init    = nand_class_init,
 };
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Andreas Färber]

Am 05.02.2014 09:39, schrieb Markus Armbruster:
> This reverts commit 7426aa72c36c908a7d0eae3e38568bb0a70de479.
> 
> The commit goes into a sensible direction, but it violates qdev design
> assumptions.  Symptom: "info qtree" crashes for all boards including
> the device (akita, borzoi, spitz, terrier, tosa, axis-dev88).
> 
> Peter Crosthwaite is working on a fix, but it's not trivial.  Revert
> the flawed patch for now.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
>  hw/block/nand.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/block/nand.c b/hw/block/nand.c
> index a871ce0..a0232d1 100644
> --- a/hw/block/nand.c
> +++ b/hw/block/nand.c
> @@ -21,7 +21,7 @@
>  # include "hw/hw.h"
>  # include "hw/block/flash.h"
>  # include "sysemu/blockdev.h"
> -#include "hw/qdev.h"
> +# include "hw/sysbus.h"
>  #include "qemu/error-report.h"
>  
>  # define NAND_CMD_READ0		0x00
> @@ -54,8 +54,7 @@
>  
>  typedef struct NANDFlashState NANDFlashState;
>  struct NANDFlashState {
> -    DeviceState parent_obj;
> -
> +    SysBusDevice busdev;

Negative on calling it busdev again, that surely has nothing to do with
a crash since it's not being used anywhere in this patch.

I still have not seen a single backtrace of what is going wrong, only
Paolo saying something about adding to main_system_bus in "the patch".
Clearly that is not in this patch! Where is that happening and why is
that so complicated for Peter C. to fix?

Andreas

>      uint8_t manf_id, chip_id;
>      uint8_t buswidth; /* in BYTES */
>      int size, pages;
> @@ -441,7 +440,7 @@ static void nand_class_init(ObjectClass *klass, void *data)
>  
>  static const TypeInfo nand_info = {
>      .name          = TYPE_NAND,
> -    .parent        = TYPE_DEVICE,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
>      .instance_size = sizeof(NANDFlashState),
>      .class_init    = nand_class_init,
>  };

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Markus Armbruster]

Andreas Färber <afaerber@suse.de> writes:

> Am 05.02.2014 09:39, schrieb Markus Armbruster:
>> This reverts commit 7426aa72c36c908a7d0eae3e38568bb0a70de479.
>> 
>> The commit goes into a sensible direction, but it violates qdev design
>> assumptions.  Symptom: "info qtree" crashes for all boards including
>> the device (akita, borzoi, spitz, terrier, tosa, axis-dev88).
>> 
>> Peter Crosthwaite is working on a fix, but it's not trivial.  Revert
>> the flawed patch for now.
>> 
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>> ---
>>  hw/block/nand.c | 7 +++----
>>  1 file changed, 3 insertions(+), 4 deletions(-)
>> 
>> diff --git a/hw/block/nand.c b/hw/block/nand.c
>> index a871ce0..a0232d1 100644
>> --- a/hw/block/nand.c
>> +++ b/hw/block/nand.c
>> @@ -21,7 +21,7 @@
>>  # include "hw/hw.h"
>>  # include "hw/block/flash.h"
>>  # include "sysemu/blockdev.h"
>> -#include "hw/qdev.h"
>> +# include "hw/sysbus.h"
>>  #include "qemu/error-report.h"
>>  
>>  # define NAND_CMD_READ0		0x00
>> @@ -54,8 +54,7 @@
>>  
>>  typedef struct NANDFlashState NANDFlashState;
>>  struct NANDFlashState {
>> -    DeviceState parent_obj;
>> -
>> +    SysBusDevice busdev;
>
> Negative on calling it busdev again, that surely has nothing to do with
> a crash since it's not being used anywhere in this patch.

I do not believe in messing with clean reverts such as this one.  Any
follow-up cleanup should be a separate patch.  The easiest way to tell
me what cleanup you want could be a patch :)

> I still have not seen a single backtrace of what is going wrong, only
> Paolo saying something about adding to main_system_bus in "the patch".
> Clearly that is not in this patch! Where is that happening and why is
> that so complicated for Peter C. to fix?

My commit message should suffice to reproduce: start a qemu for any of
the listed boards, run "info qtree".  But I'm happy to spell it out:

    $ QEMU_AUDIO_DRV=none ~/work/qemu/bld/arm-softmmu/qemu-system-arm -M akita -nodefaults -display none -monitor stdio -M akita -sd /dev/null -S
    QEMU 1.7.50 monitor - type 'help' for more information
    (qemu) info qtree
    bus: main-system-bus
      type System
      dev: scoop, id ""
        gpio-in 16
        gpio-out 16
        irq 0
        mmio 0000000010800000/0000000000001000
      dev: spitz-keyboard, id ""
        gpio-in 11
        gpio-out 7
        irq 0
      dev: nand, id ""
        manufacturer_id = 236
        chip_id = 241
        drive = <null>
    /work/armbru/qemu/hw/core/sysbus.c:209:sysbus_dev_print: Object 0x7f750ab9d910 is not an instance of type sys-bus-device
    Aborted (core dumped)

Backtrace:

    #0  0x00007fffee698c55 in raise () from /lib64/libc.so.6
    #1  0x00007fffee69a408 in abort () from /lib64/libc.so.6
    #2  0x00005555557bef59 in object_dynamic_cast_assert (obj=0x55555634d910, 
        typename=typename@entry=0x555555943e4d "sys-bus-device", file=file@entry=
        0x55555594a6f0 "/work/armbru/qemu/hw/core/sysbus.c", line=line@entry=209, 
        func=func@entry=0x55555594a940 <__func__.23193> "sysbus_dev_print")
        at /work/armbru/qemu/qom/object.c:484
    #3  0x00005555556b3c16 in sysbus_dev_print (mon=0x55555625fe00, 
        dev=<optimized out>, indent=4) at /work/armbru/qemu/hw/core/sysbus.c:209
    #4  0x00005555557a2e24 in bus_print_dev (indent=4, dev=0x55555634d910, mon=
        0x55555625fe00, bus=<optimized out>)
        at /work/armbru/qemu/qdev-monitor.c:599
    #5  qdev_print (indent=4, dev=0x55555634d910, mon=0x55555625fe00)
        at /work/armbru/qemu/qdev-monitor.c:621
    #6  qbus_print (mon=0x55555625fe00, bus=<optimized out>, indent=2)
        at /work/armbru/qemu/qdev-monitor.c:636
    #7  0x00005555558a8e39 in handle_user_command (mon=mon@entry=0x55555625fe00, 
        cmdline=<optimized out>) at /work/armbru/qemu/monitor.c:4144
    #8  0x00005555558a91cb in monitor_command_cb (opaque=0x55555625fe00, 
        cmdline=<optimized out>, readline_opaque=<optimized out>)
        at /work/armbru/qemu/monitor.c:4761
    #9  0x00005555559276b4 in readline_handle_byte (rs=0x555556273c90, 
        ch=<optimized out>) at /work/armbru/qemu/util/readline.c:371
    ---Type <return> to continue, or q <return> to quit---
    #10 0x00005555558a8f04 in monitor_read (opaque=<optimized out>, 
        buf=<optimized out>, size=<optimized out>)
        at /work/armbru/qemu/monitor.c:4744
    #11 0x00005555557a6eba in qemu_chr_be_write (len=<optimized out>, buf=
        0x7fffffffcbd0 "\r", s=0x55555625e400) at /work/armbru/qemu/qemu-char.c:165
    #12 fd_chr_read (chan=<optimized out>, cond=<optimized out>, opaque=
        0x55555625e400) at /work/armbru/qemu/qemu-char.c:848
    #13 0x00007ffff76f7a55 in g_main_context_dispatch ()
       from /lib64/libglib-2.0.so.0
    #14 0x0000555555775001 in glib_pollfds_poll ()
        at /work/armbru/qemu/main-loop.c:189
    #15 os_host_main_loop_wait (timeout=<optimized out>)
        at /work/armbru/qemu/main-loop.c:234
    #16 main_loop_wait (nonblocking=<optimized out>)
        at /work/armbru/qemu/main-loop.c:483
    #17 0x0000555555601ed1 in main_loop () at /work/armbru/qemu/vl.c:2018
    #18 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>)
        at /work/armbru/qemu/vl.c:4410

As to why it's complicated for Peter to fix, here's what Peter wrote:
"That series got very big on me with complications.  I think near term
we just proceed with the revert.  Sorry for the delay."  I have no
reason to second-guess him.

Promptly reverting patches that cause regressions when a fix isn't ready
is standard operating procedure.  We can delay a revert a reasonable
amount of time to deliberate what to do, and perhaps find a fix.  We did
that, and then some: four weeks.  We should revert, and try again.
Neither harm nor shame in that.

A cleanup of nand is quite welcome, but there's absolutely no rush.

[...]

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Peter Maydell]

On 5 February 2014 12:24, Markus Armbruster <armbru@redhat.com> wrote:
> As to why it's complicated for Peter to fix, here's what Peter wrote:
> "That series got very big on me with complications.  I think near term
> we just proceed with the revert.  Sorry for the delay."  I have no
> reason to second-guess him.
>
> Promptly reverting patches that cause regressions when a fix isn't ready
> is standard operating procedure.  We can delay a revert a reasonable
> amount of time to deliberate what to do, and perhaps find a fix.  We did
> that, and then some: four weeks.  We should revert, and try again.
> Neither harm nor shame in that.

I agree in general here, which is why I'm going to apply this patch.

While we're talking about regressions: Paolo, do we have a good
fix for the PPC boot regression yet or should we revert the patch which
caused that?

thanks
-- PMM

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Peter Maydell]

On 5 February 2014 13:00, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 5 February 2014 12:24, Markus Armbruster <armbru@redhat.com> wrote:
>> As to why it's complicated for Peter to fix, here's what Peter wrote:
>> "That series got very big on me with complications.  I think near term
>> we just proceed with the revert.  Sorry for the delay."  I have no
>> reason to second-guess him.
>>
>> Promptly reverting patches that cause regressions when a fix isn't ready
>> is standard operating procedure.  We can delay a revert a reasonable
>> amount of time to deliberate what to do, and perhaps find a fix.  We did
>> that, and then some: four weeks.  We should revert, and try again.
>> Neither harm nor shame in that.
>
> I agree in general here, which is why I'm going to apply this patch.

Following conversation on IRC and Andreas' recent patch:
given that the current state of affairs (ie 'info qtest crashes') has been
in master for six months, there doesn't seem to be a critically urgent
need to act immediately, so I'm going to give it a few days to check
that we have a consensus on the best way to deal with this.

thanks
-- PMM

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Markus Armbruster]

Peter Maydell <peter.maydell@linaro.org> writes:

> On 5 February 2014 13:00, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 5 February 2014 12:24, Markus Armbruster <armbru@redhat.com> wrote:
>>> As to why it's complicated for Peter to fix, here's what Peter wrote:
>>> "That series got very big on me with complications.  I think near term
>>> we just proceed with the revert.  Sorry for the delay."  I have no
>>> reason to second-guess him.
>>>
>>> Promptly reverting patches that cause regressions when a fix isn't ready
>>> is standard operating procedure.  We can delay a revert a reasonable
>>> amount of time to deliberate what to do, and perhaps find a fix.  We did
>>> that, and then some: four weeks.  We should revert, and try again.
>>> Neither harm nor shame in that.
>>
>> I agree in general here, which is why I'm going to apply this patch.
>
> Following conversation on IRC and Andreas' recent patch:
> given that the current state of affairs (ie 'info qtest crashes') has been
> in master for six months, there doesn't seem to be a critically urgent
> need to act immediately, so I'm going to give it a few days to check
> that we have a consensus on the best way to deal with this.

Waiting a few more days for a fix is fine with me.

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Paolo Bonzini]

Il 05/02/2014 14:00, Peter Maydell ha scritto:
> While we're talking about regressions: Paolo, do we have a good
> fix for the PPC boot regression yet or should we revert the patch which
> caused that?

Yes, Antony tested the patch on Xen.  I'll send the patch as soon as 
possible.

Paolo

Re: [Qemu-devel] [PATCH] Revert "nand: Don't inherit from Sysbus"

[Peter Crosthwaite]

On Wed, Feb 5, 2014 at 6:55 PM, Andreas Färber <afaerber@suse.de> wrote:
> Am 05.02.2014 09:39, schrieb Markus Armbruster:
>> This reverts commit 7426aa72c36c908a7d0eae3e38568bb0a70de479.
>>
>> The commit goes into a sensible direction, but it violates qdev design
>> assumptions.  Symptom: "info qtree" crashes for all boards including
>> the device (akita, borzoi, spitz, terrier, tosa, axis-dev88).
>>
>> Peter Crosthwaite is working on a fix, but it's not trivial.  Revert
>> the flawed patch for now.
>>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>> ---
>>  hw/block/nand.c | 7 +++----
>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/block/nand.c b/hw/block/nand.c
>> index a871ce0..a0232d1 100644
>> --- a/hw/block/nand.c
>> +++ b/hw/block/nand.c
>> @@ -21,7 +21,7 @@
>>  # include "hw/hw.h"
>>  # include "hw/block/flash.h"
>>  # include "sysemu/blockdev.h"
>> -#include "hw/qdev.h"
>> +# include "hw/sysbus.h"
>>  #include "qemu/error-report.h"
>>
>>  # define NAND_CMD_READ0              0x00
>> @@ -54,8 +54,7 @@
>>
>>  typedef struct NANDFlashState NANDFlashState;
>>  struct NANDFlashState {
>> -    DeviceState parent_obj;
>> -
>> +    SysBusDevice busdev;
>
> Negative on calling it busdev again, that surely has nothing to do with
> a crash since it's not being used anywhere in this patch.
>
> I still have not seen a single backtrace of what is going wrong, only
> Paolo saying something about adding to main_system_bus in "the patch".
> Clearly that is not in this patch! Where is that happening and why is
> that so complicated for Peter C. to fix?
>

Im not going after the info-qtree side fix. I was looking at the
proper busification of NAND. There are possible core fixes to restore
the info-qtree behaviour without this revert, but even if you do, the
information presented by info qtree is bogus, because nand devices to
not attach to root system buses.

Regards,
Peter

> Andreas
>
>>      uint8_t manf_id, chip_id;
>>      uint8_t buswidth; /* in BYTES */
>>      int size, pages;
>> @@ -441,7 +440,7 @@ static void nand_class_init(ObjectClass *klass, void *data)
>>
>>  static const TypeInfo nand_info = {
>>      .name          = TYPE_NAND,
>> -    .parent        = TYPE_DEVICE,
>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>>      .instance_size = sizeof(NANDFlashState),
>>      .class_init    = nand_class_init,
>>  };
>
> --
> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
>