[PATCH] i386/cpu: fixup number of addressable IDs for logical processors in the physical package

[Chuang Xu]

As (1+CPUID.04H.EAX[31:26]) round up to the nearest power-of-2 integer,
we'd beter round up CPUID.01H.EBX[23:16] to the nearest power-of-2
integer too. Otherwise we may encounter unexpected results in guest.

For example, some guest os uses CPUID.01H.EBX[23:16]/(1+CPUID.04H.EAX[31:26])
to calculate threads-per-core, if we have 90 ht (45 core) in the
package, we'll get "90/(1+63)=1" as the result, even though
theads-per-core should actually be 2.

So let us round up CPUID.01H.EBX[23:16] to the nearest power-of-2 integer
to solve the unexpected result.

Signed-off-by: Guixiong Wei <weiguixiong@bytedance.com>
Signed-off-by: Yipeng Yin <yinyipeng@bytedance.com>
Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com>
---
 target/i386/cpu.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 4c2e6f3a71..24d60ead9e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -261,6 +261,12 @@ static uint32_t max_thread_ids_for_cache(X86CPUTopoInfo 
*topo_info,
     return num_ids - 1;
 }
 
+static uint32_t max_thread_number_in_package(X86CPUTopoInfo *topo_info)
+{
+    uint32_t num_threads = 1 << apicid_pkg_offset(topo_info);
+    return num_threads;
+}
+
 static uint32_t max_core_ids_in_package(X86CPUTopoInfo *topo_info)
 {
     uint32_t num_cores = 1 << (apicid_pkg_offset(topo_info) -
@@ -6417,7 +6423,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
         }
         *edx = env->features[FEAT_1_EDX];
         if (threads_per_pkg > 1) {
-            *ebx |= threads_per_pkg << 16;
+            *ebx |= max_thread_number_in_package(&topo_info) << 16;
             *edx |= CPUID_HT;
         }
         if (!cpu->enable_pmu) {
-- 
2.20.1