Re: [Qemu-devel] [PULL 0/3] Trivial branch patches

[Laurent Vivier]

> Le 3 juil. 2019 à 17:22, Laurent Vivier <address@hidden> a écrit :
> 
> Le 03/07/2019 à 16:45, Peter Maydell a écrit :
>> On Tue, 2 Jul 2019 at 13:39, Laurent Vivier <address@hidden> wrote:
>>> 
>>> The following changes since commit 7d0e02405fc02a181319b1ab8681d2f72246b7c6:
>>> 
>>>  Merge remote-tracking branch 
>>> 'remotes/vivier2/tags/trivial-patches-pull-request' into staging 
>>> (2019-07-01 17:40:32 +0100)
>>> 
>>> are available in the Git repository at:
>>> 
>>>  git://github.com/vivier/qemu.git tags/trivial-branch-pull-request
>>> 
>>> for you to fetch changes up to 7c955080d40ccc7952a0479bc160f2b048c0af53:
>>> 
>>>  docs/devel/testing: Fix typo in dockerfile path (2019-07-02 10:12:32 +0200)
>>> 
>>> ----------------------------------------------------------------
>>> Fix typo, fix sys_cache_info() on FreeBSD/powerpc,
>>> change virtio-rng default to urandom
>>> 
>>> ----------------------------------------------------------------
>> 
>> Hi; this makes 'make check' fail on OSX:
>> 
>> MALLOC_PERTURB_=${MALLOC_PERTURB_:-$(( ${RANDOM:-0} % 255 + 1))}
>> tests/test-char -m=quick -k --tap < /dev/null |
>> ./scripts/tap-driver.pl --test-name="test-char"
>> Assertion failed: ((isize & (isize - 1)) == 0), function
>> init_cache_info, file
>> /Users/pm215/src/qemu-for-merges/util/cacheinfo.c, line 179.
>> 
>> I guess this is the sys_cache_info change.
> 
> OK, I will try to reproduce the problem.
> 
> I think before this patch (regarding the kind of change we have
> introduced) isize and dsize were always set to 0 and then changed to 16
> in fallback_cache_info()... or perhaps MacOS X sysctlbyname() needs a long.

It seems MacOS X (x86_64) needs a long:

#include <stdio.h>
#include <sys/types.h>
#include <sys/sysctl.h>

int main(void)
{
        long size;
        int ret;
        size_t len = sizeof(size);
        ret = sysctlbyname("hw.cachelinesize", &size, &len, NULL, 0);
        printf("ret %d size 0x%lx\n", ret, size);
        return 0;
}
$ cc -o cachesize cachesize.c
$ ./cachesize 
ret 0 size 0x40

#include <stdio.h>
#include <sys/types.h>
#include <sys/sysctl.h>

int main(void)
{
        int size;
        int ret;
        size_t len = sizeof(size);
        ret = sysctlbyname("hw.cachelinesize", &size, &len, NULL, 0);
        printf("ret %d size 0x%x\n", ret, size);
        return 0;
}
$ cc -o cachesize cachesize.c
$ ./cachesize 
ret 0 size 0x1737b1d2
$ sysctl hw.cachelinesize
hw.cachelinesize: 64

But man page is not up-to-date:

$ uname -r
17.7.0
$ man sysctl
SYSCTL(8)                 BSD System Manager's Manual                SYSCTL(8)
…
     The string and integer information is summarized below.  For a detailed
     description of these variable see sysctl(3).

     The changeable column indicates whether a process with appropriate privi-
     lege can change the value.  String and integer values can be set using
     sysctl.

     Name                                        Type          Changeable
…
     hw.cachelinesize                            integer       no
…

In fact, it is in sysctl(3):

SYSCTL(3)                BSD Library Functions Manual                SYSCTL(3)
…
   CTL_HW
     The string and integer information available for the CTL_HW level is
     detailed below.  The changeable column shows whether a process with
     appropriate privilege may change the value.

           Name                         Type          Changeable
...
           hw.cachelinesize             int64_t       no

I will try to check on MacOS/X ppc and ppc64.

Thanks,
Laurent