Re: [Qemu-devel] [PULL 11/13] target-i386: forward CPUID cache leaves when -cpu host is used

[Paolo Bonzini]

Il 19/11/2013 13:03, Peter Lieven ha scritto:
>>
>> Can you test which of these two work?  But I agree it's best to disable
>> cache-leaf forwarding.
> The first does make windows boot again and it calculates a
> correct combination of cpus, threads, cores and sockets. But
> I think the reason it boots is because cores=threads=1.
> 
> As its more intuitive (I think) I would prefer your "cores over threads
> over socket ".
> The last thing I would think of is emulating more than 1 socket. -smp N
> would then mean, N cores, no hyper-threading, 1 socket.

After looking more at the docs, I think I found the bug.  Can you test this?

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 864c80e..16d4db1 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -2086,14 +2086,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
         /* cache info: needed for Core compatibility */
         if (cpu->cache_info_passthrough) {
             host_cpuid(index, count, eax, ebx, ecx, edx);
-            break;
-        }
-        if (cs->nr_cores > 1) {
-            *eax = (cs->nr_cores - 1) << 26;
+            *eax &= ~0xFC000000;
         } else {
             *eax = 0;
-        }
-        switch (count) {
+            switch (count) {
             case 0: /* L1 dcache info */
                 *eax |= CPUID_4_TYPE_DCACHE | \
                         CPUID_4_LEVEL(1) | \
@@ -2118,9 +2114,6 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
                 *eax |= CPUID_4_TYPE_UNIFIED | \
                         CPUID_4_LEVEL(2) | \
                         CPUID_4_SELF_INIT_LEVEL;
-                if (cs->nr_threads > 1) {
-                    *eax |= (cs->nr_threads - 1) << 14;
-                }
                 *ebx = (L2_LINE_SIZE - 1) | \
                        ((L2_PARTITIONS - 1) << 12) | \
                        ((L2_ASSOCIATIVITY - 1) << 22);
@@ -2133,6 +2126,12 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
                 *ecx = 0;
                 *edx = 0;
                 break;
+            }
+        }
+
+        /* We give out APIC IDs ourselves, so force bits 31..26 even for "-cpu 
host".  */
+        if (cs->nr_cores > 1) {
+            *eax |= (cs->nr_cores - 1) << 26;
         }
         break;
     case 5:

Paolo