qmp_command: qmp_memsave test uses invalid virtual address

[rayx]

qmp_memsave failed on aarch64 with this error:

 
11:00:49 ERROR| TestFail: QMP command 'memsave' failed    (arguments: {'filename': '/var/tmp/memsave', 'val': 0, 'size': 4096},    error message: {u'class': u'GenericError', u'desc': u'Invalid addr 0x0000000000000000/size 4096 specified'})

Does this test works on x86_64? I doubt it because from my understanding 0x0 address is usually not mapped.

I think the test should be modified to use a valid virtual address. Below is the approach I use in my manual experiment (I choose _text symbol because I suppose it's available on all archs):

 
$ sudo cat /proc/kallsyms | grep -w _text | awk '{print $1}'
ffff000008080000

[rayx]

Just in case it's not clear, the command should be run in guest.

[vivianQizhu]

@jingzhao84 @huangyum Would you help check this? Thanks.

[jingzhao84]

x86_64 didn't execute this command now, since https://bugzilla.redhat.com/show_bug.cgi?id=1116315

[rayx]

@jingzhao84 The bug in bugzilla is the same issue. But I don't think it's a QEMU issue, it's a test issue instead. Test should pass a valid virtual address in the guest. Otherwise QEMU can't translate it to a physical address (it does so by checking page tables in guest) and hence the error.

[jingzhao84]

@rayx developer think no high level tool used it, so they will not fix it.