Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2

[Laszlo Ersek]

On 07/13/17 00:27, Michael S. Tsirkin wrote:
> On Wed, Jul 12, 2017 at 05:56:46PM -0300, Eduardo Habkost wrote:
>> On Wed, Jul 12, 2017 at 11:31:59PM +0300, Michael S. Tsirkin wrote:
>>> On Wed, Jul 12, 2017 at 05:15:50PM -0300, Eduardo Habkost wrote:
>>>> On Wed, Jul 12, 2017 at 06:17:55PM +0300, Michael S. Tsirkin wrote:
>>>>> On Wed, Jul 12, 2017 at 11:51:21AM -0300, Eduardo Habkost wrote:
>>>>>> On Wed, Jul 12, 2017 at 10:22:33AM +0200, Thomas Huth wrote:
>>>>>>> We don't want to carry along old machine types forever. If we are able 
>>>>>>> to
>>>>>>> remove the pc machines up to 0.13 one day for example, this would allow
>>>>>>> us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM
>>>>>>> BARs directly to low memory). Everything up to pc-1.2 is also known to
>>>>>>> have issues with migration.  So let's start with a deprecation message
>>>>>>> for the old machine types so that the (hopefully) few users of these old
>>>>>>> systems start switching over to newer machine types instead.
>>>>>>>
>>>>>>> Signed-off-by: Thomas Huth <address@hidden>
>>>>>>
>>>>>> Reviewed-by: Eduardo Habkost <address@hidden>
>>>>>>
>>>>>> I suggest changing "-machine help" too.  Today it looks like this:
>>>>>>
>>>>>>   Supported machines are:
>>>>>>   pc-i440fx-2.9        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.8        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.7        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.6        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.5        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.4        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.3        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.2        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc                   Standard PC (i440FX + PIIX, 1996) (alias of 
>>>>>> pc-i440fx-2.10)
>>>>>>   pc-i440fx-2.10       Standard PC (i440FX + PIIX, 1996) (default)
>>>>>>   pc-i440fx-2.1        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-2.0        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-1.7        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-1.6        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-1.5        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-i440fx-1.4        Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-1.3               Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-1.2               Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-1.1               Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-1.0               Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.15              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.14              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.13              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.12              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.11              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-0.10              Standard PC (i440FX + PIIX, 1996)
>>>>>>   pc-q35-2.9           Standard PC (Q35 + ICH9, 2009)
>>>>>>   pc-q35-2.8           Standard PC (Q35 + ICH9, 2009)
>>>>>>   pc-q35-2.7           Standard PC (Q35 + ICH9, 2009)
>>>>>>   pc-q35-2.6           Standard PC (Q35 + ICH9, 2009)
>>>>>>   pc-q35-2.5           Standard PC (Q35 + ICH9, 2009)
>>>>>>   pc-q35-2.4           Standard PC (Q35 + ICH9, 2009)
>>>>>>   q35                  Standard PC (Q35 + ICH9, 2009) (alias of 
>>>>>> pc-q35-2.10)
>>>>>>   pc-q35-2.10          Standard PC (Q35 + ICH9, 2009)
>>>>>>   isapc                ISA-only PC
>>>>>>   none                 empty machine
>>>>>
>>>>> Any chance we can sort them reasonably too?
>>>>
>>>> If we use strverscmp(), it will be sorted in a more reasonable
>>>> way.  We could copy the gnulib version on systems without glibc.
>>>> Life is too short for writing configure checks by hand, though; I
>>>> will add this to the end of my wish-todo list.  If somebody wants
>>>> to volunteer, be my guest.
>>>>
>>>> I'm CCing Eric in case he has suggestions that would help import
>>>> the gnulib module in an easy way.
>>>>
>>>> -- 
>>>> Eduardo
>>>
>>> As we never have leading zeroes, and input comes from QEMU so
>>> it's safe, it's probably easier to just open-code it:
>>>
>>> /* compare string numerically: shorter strings give smaller numbers */
>>> int mstcmp(const char *s1, const char *s2)
>>> {
>>>     int l1, l2;
>>>
>>>     l1 = strlen(s1);
>>>     l2 = strlen(s2);
>>>     return l1 == l2 ? strcmp(s1, s2) : l1 - l2;
>>> }
>>>
>>
>> This doesn't work because strlen("pc-0.10") > strlen("pc-1.0").
> 
> Oh right. So you need to find dots and split at these points.
> Something like the below? Completely untested.
> 
> int mstcmp(const char *s1, const char *s2)
> {
>       const char *e1, *e2;
>       int l1, l2, c;
> 
>       do {
>               e1 = strchr(s1, '.');
>               e2 = strchr(s2, '.');
> 
>               l1 = e1 ? e1 - s1 + 1 : strlen(s1);
>               l2 = e2 ? e2 - s2 + 1 : strlen(s2);
> 
>               /* compare numerically: shorter strings give smaller numbers */
>               if (l1 != l2) {
>                       break;
>               }
>               c = strncmp(s1, s2, l1);
>               if (c) {
>                       return c;
>               }
>               s1 += l1;
>               s2 += l1;
>       } while (l1);
> 
>       return l1 - l2;
> }

QEMU already has machine type sorting code:

  1  2709f263952b well-defined listing order for machine types
  2  562542b6aee2 i386/pc: add piix and q35 machtypes to sorting
                  families for -M \?

I guess it should be possible to refine machine_class_cmp() in "vl.c",
so that some numeric sorting is applied to machine types in the same
"family".

Thanks
Laszlo