[Qemu-devel] Re: [PATCH][SEABIOS] Make SMBIOS table pass MS SVVP test

["Sebastian Herbszt" <herbszt@gmx.de>]

Gleb Natapov wrote:
> On Wed, Nov 25, 2009 at 09:09:19PM +0100, Sebastian Herbszt wrote:
>> Gleb Natapov wrote:
>> >On Tue, Nov 24, 2009 at 10:57:02AM -0500, Kevin O'Connor wrote:
>> >>
>> >>That said, I think SeaBIOS should autodetect any values where that's
>> >>feasible.  So, for example, if the cpu identification is available via
>> >>cpuid, then I think that should be used.  However, for example, if cpu
>> >>model isn't available anywhere, then I think hardcoding something is
>> >>okay.
>> >It is used already where appropriate. To fill processor_id field in type
>> >4 table. CPU manufacturer is different issue. CPU a guest is running on is
>> >not manufactured by Intel or AMD, it is emulated by QEMU.
>> 
>> I am still wondering why you're against using the vendor reported by CPUID.
> I am still wondering why you want this :) But let me ask you a question:
> You are running some program inside QEMU and you encounter a bug. Some
> instruction does not update eflags like it should and program fails. Do
> you complain to
> a) AMD
> b) Intel
> c) QEMU mailing list.
> 
> If your answer is (c), then I don't see how you can propose to put
> something else then QEMU in manufacturer field.

Since i know i run the program inside QEMU my answer has to be (c). On the other
hand the competition doesn't put "VMware" there.

>> The cross vendor host cpu migration doesn't seem to be a sound reason, because
>> the cpu in the guest is emulated and has no relationship to the host cpu.
>> If i specify "-cpu phenom", i end up with an AMD cpu. Since noone but AMD
>> produces this cpu it seems only reasonable to advertise the vendor as AMD.
>> 
>> >>> > >>>>>>>-    p->max_speed = 0; /* unknown */
>> >>> > >>>>>>>-    p->current_speed = 0; /* unknown */
>> >>> > >>>>>>>+    p->max_speed = 2000;
>> >>> > >>>>>>>+    p->current_speed = 2000;
>> >>
>> >>SeaBIOS detects the current Mhz - see calibrate_tsc() in src/clock.c.
>> >>
>> >How accurate is it? What if I boot 100 guests on 16 cpu host
>> >simultaneously? Not uncommon scenario. Those field really have no
>> >meaning in virtualization environment. I'd rather have predictable
>> >values there from boot to boot. Who know what Windows may use them for.
>> 
>> Speaking of not knowing what an OS or application might do with values in the
>> SMBIOS table. Doesn't the same argument apply to the cpu vendor?
>> 
> I am concern with SMBIOS table be different on each boot, not what
> information is stored in those fields. CPU manufacturer is free form
> string. I have computers that have "Intel" there, others have "Intel(R)
> Corporation". As long as it consistent from boot to boot it is OK IMO.

Then i must admit i understood your  "Who know what Windows may use them for"
statement different.

- Sebastian