On 7/17/20 9:18 PM, Havard Skinnemoen wrote:
> On Fri, Jul 17, 2020 at 2:00 AM Philippe Mathieu-Daudé <f4...@amsat.org>
> wrote:
>>
>> On 7/17/20 10:27 AM, Philippe Mathieu-Daudé wrote:
>>> On 7/17/20 10:03 AM, Thomas Huth wrote:
>>>> On 17/07/2020 09.48, Philippe Mathieu-Daudé wrote:
>>>>> +Thomas
>>>>
>>>>> On 7/16/20 10:56 PM, Havard Skinnemoen wrote:
>>>>>> On Wed, Jul 15, 2020 at 1:54 PM Havard Skinnemoen
>>>>>> <hskinnem...@google.com> wrote:
>>>>>>>
>>>>>>> On Wed, Jul 15, 2020 at 3:57 AM Philippe Mathieu-Daudé
>>>>>>> <f4...@amsat.org> wrote:
>>>>>>>>
>>>>>>>> On 7/15/20 11:00 AM, Markus Armbruster wrote:
>>>>>>>>> Now my point. Why first make up user configuration, then use that to
>>>>>>>>> create a BlockBackend, when you could just go ahead and create the
>>>>>>>>> BlockBackend?
>>>>>>>>
>>>>>>>> CLI issue mostly.
>>>>>>>>
>>>>>>>> We can solve it similarly to the recent "sdcard: Do not allow invalid
>>>>>>>> SD
>>>>>>>> card sizes" patch:
>>>>>>>>
>>>>>>>> if (!dinfo) {
>>>>>>>> error_setg(errp, "Missing SPI flash drive");
>>>>>>>> error_append_hint(errp, "You can use a dummy drive using:\n");
>>>>>>>> error_append_hint(errp, "-drive if=mtd,driver=null-co,"
>>>>>>>> "read-ones=on,size=64M\n);
>>>>>>>> return;
>>>>>>>> }
>>>>>>>>
>>>>>>>> having npcm7xx_connect_flash() taking an Error* argument,
>>>>>>>> and MachineClass::init() call it with &error_fatal.
>>>>>>>
>>>>>>> Erroring out if the user specifies a configuration that can't possibly
>>>>>>> boot sounds good to me. Better than trying to come up with defaults
>>>>>>> that are still not going to result in a bootable system.
>>>>>>>
>>>>>>> For testing recovery paths, I think it makes sense to explicitly
>>>>>>> specify a null device as you suggest.
>>>>>>
>>>>>> Hmm, one problem. qom-test fails with
>>>>>>
>>>>>> qemu-system-aarch64: Missing SPI flash drive
>>>>>> You can add a dummy drive using:
>>>>>> -drive if=mtd,driver=null-co,read-zeroes=on,size=32M
>>>>>> Broken pipe
>>>>>> /usr/local/google/home/hskinnemoen/qemu/for-upstream/tests/qtest/libqtest.c:166:
>>>>>> kill_qemu() tried to terminate QEMU process but encountered exit
>>>>>> status 1 (expected 0)
>>>>>> ERROR qom-test - too few tests run (expected 68, got 7)
>>>>>>
>>>>>> So it looks like we might need a different solution to this, unless we
>>>>>> want to make generic tests more machine-aware...
>>>>
>>>> I didn't follow the other mails in this thread, but what we usually do
>>>> in such a case: Add a "if (qtest_enabled())" check to the device or the
>>>> machine to ignore the error if it is running in qtest mode.
>>>
>>> Hmm I'm not sure it works in this case. We could do:
>>>
>>> if (!dinfo) {
>>> if (qtest) {
>>> /* create null drive for qtest */
>>> opts = ...;
>>> dinfo = drive_new(opts, IF_MTD, &error_abort);
>>> } else {
>>> /* teach user to use proper CLI */
>>> error_setg(errp, "Missing SPI flash drive");
>>> error_append_hint(errp, "You can use a dummy drive using:\n");
>>> error_append_hint(errp, "-drive if=mtd,driver=null-co,"
>>> "read-ones=on,size=64M\n);
>>> }
>>> }
>>>
>>> But I'm not sure Markus will enjoy it :)
>>>
>>> Markus, any better idea about how to handle that with automatic qtests?
>>
>> FWIW IDE device has a concept of "Anonymous BlockBackend for an empty
>> drive":
>>
>> static void ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind, Error **errp)
>> {
>> IDEBus *bus = DO_UPCAST(IDEBus, qbus, dev->qdev.parent_bus);
>> IDEState *s = bus->ifs + dev->unit;
>> int ret;
>>
>> if (!dev->conf.blk) {
>> if (kind != IDE_CD) {
>> error_setg(errp, "No drive specified");
>> return;
>> } else {
>> /* Anonymous BlockBackend for an empty drive */
>> dev->conf.blk = blk_new(qemu_get_aio_context(), 0,
>> BLK_PERM_ALL);
>> ret = blk_attach_dev(dev->conf.blk, &dev->qdev);
>> assert(ret == 0);
>> }
>> }
>
> Could someone please remind me what problem we're trying to solve here?
>
> Currently, if the user (or test) doesn't provide a drive, we pass NULL
> as the block backend to m25p80. This means we'll take the code path in
> m25p_realize() that does
>
> trace_m25p80_binding_no_bdrv(s);
> s->storage = blk_blockalign(NULL, s->size);
> memset(s->storage, 0xFF, s->size);
>
> which will look like a freshly chip-erased flash chip.
which is perfect.
C.
