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

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/11/2013 15:17, Peter Lieven ha scritto:
>> if ((*eax & 31) && cs->nr_cores > 1)
> at which position exactly do you want to put this condition and take
> which action?

Just replace "if (cs->nr_cores > 1)" in the patch I posted, i.e. after the switch.

Paolo

-------------- 8< -----------------
>From 781ff96e9d1eeacbd4ff588d4d3773351f14320b Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 19 Nov 2013 13:19:17 +0100
Subject: [PATCH] target-i386: do not override nr_cores for "-cpu host"

Commit 787aaf5 (target-i386: forward CPUID cache leaves when -cpu host is
used, 2013-09-02) brings bits 31..26 of CPUID leaf 04h out of sync with
the APIC IDs that QEMU reserves for each package.  This number must come
from "-smp" options rather than from the host CPUID.

It also turns out that this unsyncing makes Windows Server 2012R2 fail
to boot.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target-i386/cpu.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 864c80e..8df6747 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) | \
@@ -2133,6 +2129,12 @@ 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 ((*eax & 31) && cs->nr_cores > 1) {
+            *eax |= (cs->nr_cores - 1) << 26;
         }
         break;
     case 5:
-- 
1.8.4.2