[PULL 04/25] target/i386: Make invtsc migratable when user sets tsc-khz explicitly

[Paolo Bonzini <pbonzini@redhat.com>]

From: Xiaoyao Li <xiaoyao.li@intel.com>

When user sets tsc-frequency explicitly, the invtsc feature is actually
migratable because the tsc-frequency is supposed to be fixed during the
migration.

See commit d99569d9d856 ("kvm: Allow invtsc migration if tsc-khz
is set explicitly") for referrence.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20240814075431.339209-10-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 089b651591b..5535f4e6ab4 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1865,9 +1865,10 @@ static inline uint64_t x86_cpu_xsave_xss_components(X86CPU *cpu)
  * Returns the set of feature flags that are supported and migratable by
  * QEMU, for a given FeatureWord.
  */
-static uint64_t x86_cpu_get_migratable_flags(FeatureWord w)
+static uint64_t x86_cpu_get_migratable_flags(X86CPU *cpu, FeatureWord w)
 {
     FeatureWordInfo *wi = &feature_word_info[w];
+    CPUX86State *env = &cpu->env;
     uint64_t r = 0;
     int i;
 
@@ -1881,6 +1882,12 @@ static uint64_t x86_cpu_get_migratable_flags(FeatureWord w)
             r |= f;
         }
     }
+
+    /* when tsc-khz is set explicitly, invtsc is migratable */
+    if ((w == FEAT_8000_0007_EDX) && env->user_tsc_khz) {
+        r |= CPUID_APM_INVTSC;
+    }
+
     return r;
 }
 
@@ -6124,7 +6131,7 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w)
 
     r &= ~unavail;
     if (cpu && cpu->migratable) {
-        r &= x86_cpu_get_migratable_flags(w);
+        r &= x86_cpu_get_migratable_flags(cpu, w);
     }
     return r;
 }
-- 
2.46.2