CPUID.8000001DH:EAX[25:14] is "NumSharingCache", and the number of
logical processors sharing this cache is the value of this field
incremented by 1. Because of its width limitation, the maximum value
currently supported is 4095.

Though at present Q35 supports up to 4096 CPUs, to prevent potential
overflow issues from further increasing the number of CPUs in the
future, check and honor the maximum value as CPUID.04H did.

Cc: Babu Moger <babu.moger@amd.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
RFC:
 * Although there are currently no overflow cases, to avoid any
   potential issue, add the overflow check, just as I did for Intel.
---
 target/i386/cpu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d75175b0850a..7ca9740e8c97 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -493,7 +493,8 @@ static void encode_cache_cpuid8000001d(CPUCacheInfo *cache,
 
     *eax = CACHE_TYPE(cache->type) | CACHE_LEVEL(cache->level) |
                (cache->self_init ? CACHE_SELF_INIT_LEVEL : 0);
-    *eax |= max_thread_ids_for_cache(topo_info, cache->share_level) << 14;
+    /* Bits 25:14 - NumSharingCache: maximum 4095. */
+    *eax |= MIN(max_thread_ids_for_cache(topo_info, cache->share_level), 4095) << 14;
 
     assert(cache->line_size > 0);
     assert(cache->partitions > 0);
-- 
2.34.1