[Qemu-devel] seabios: missing DMI type 4 entry if -cpu parameter is used

[Qemu-devel] seabios: missing DMI type 4 entry if -cpu parameter is used

[Sebastian Herbszt]

v0.11.0-rc0-1677:
use -cpu pentium and check SMBIOS tables. DMI type 4 entry is missing.
Works with Bochs bios.

- Sebastian

Re: [Qemu-devel] seabios: missing DMI type 4 entry if -cpu parameter is used

[Gleb Natapov]

On Sun, Nov 22, 2009 at 06:05:02PM +0100, Sebastian Herbszt wrote:
> v0.11.0-rc0-1677:
> use -cpu pentium and check SMBIOS tables. DMI type 4 entry is missing.
> Works with Bochs bios.
> 
See two problems here. First one in seabios (patch attached). And the
second one in QEMU. Why pentium cpu type lacks apic? Specifying 
-cpu pentium,+apic works with current seabios without the patch.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/src/smp.c b/src/smp.c
index 7100476..00cf64b 100644
--- a/src/smp.c
+++ b/src/smp.c
@@ -75,7 +75,9 @@ smp_probe(void)
     cpuid(1, &eax, &ebx, &ecx, &cpuid_features);
     if (! (cpuid_features & CPUID_APIC)) {
         // No apic - only the main cpu is present.
+        dprintf(1, "No apic - only the main cpu is present.\n");
         CountCPUs= 1;
+        MaxCountCPUs = 1;
         return;
     }
 
--
			Gleb.

Re: [Qemu-devel] seabios: missing DMI type 4 entry if -cpu parameter is used

[Sebastian Herbszt]

Gleb Natapov wrote:
> On Sun, Nov 22, 2009 at 06:05:02PM +0100, Sebastian Herbszt wrote:
>> v0.11.0-rc0-1677:
>> use -cpu pentium and check SMBIOS tables. DMI type 4 entry is missing.
>> Works with Bochs bios.
>> 
> See two problems here. First one in seabios (patch attached). And the
> second one in QEMU. Why pentium cpu type lacks apic? Specifying 
> -cpu pentium,+apic works with current seabios without the patch.

The "Pentium Processor Family Developer's Manual, Volume 3: Architecture
and Programming Manual" says the following in Chapter 19.3:

"APIC IS SUPPORTED ONLY ON PENTIUM PROCESSOR (735\90, 815\100,
1000\120, 1110\133) AND FUTURE PROLIFERATIONS AND UPGRADES."

So it seems not all pentium cpus have an apic. No clue which model and stepping
those are so can't compare to what qemu claims to provide.

- Sebastian

Re: [Qemu-devel] seabios: missing DMI type 4 entry if -cpu parameter is used

[Kevin O'Connor]

On Mon, Nov 23, 2009 at 03:00:43PM +0200, Gleb Natapov wrote:
> On Sun, Nov 22, 2009 at 06:05:02PM +0100, Sebastian Herbszt wrote:
> > v0.11.0-rc0-1677:
> > use -cpu pentium and check SMBIOS tables. DMI type 4 entry is missing.
> > Works with Bochs bios.
> > 
> See two problems here. First one in seabios (patch attached). And the
> second one in QEMU. Why pentium cpu type lacks apic? Specifying 
> -cpu pentium,+apic works with current seabios without the patch.
> 
> Signed-off-by: Gleb Natapov <gleb@redhat.com>

Thanks - commit b49e1e38.

-Kevin