[2/3] target/i386: call cpu_exec_realizefn before x86_cpu_filter_features

Commit Message

Chen, Zide May 20, 2024, 5:47 p.m. UTC

cpu_exec_realizefn which calls the accel-specific realizefn may expand
features.  e.g., some accel-specific options may require extra features
to be enabled, and it's appropriate to expand these features in accel-
specific realizefn.

One such example is the cpu-pm option, which may add CPUID_EXT_MONITOR.

Thus, call cpu_exec_realizefn before x86_cpu_filter_features to ensure
that it won't expose features not supported by the host.

Fixes: 662175b91ff2 ("i386: reorder call to cpu_exec_realizefn")
Suggested-by: Xiaoyao Li <[e-mail]>
Signed-off-by: Zide Chen <[e-mail]>
---
 target/i386/cpu.c         | 24 ++++++++++++------------
 target/i386/kvm/kvm-cpu.c |  1 -
 2 files changed, 12 insertions(+), 13 deletions(-)

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index cfe7c92d6bc6..da1ab7892d26 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7438,6 +7438,18 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
         }
     }
 
+    /*
+     * note: the call to the framework needs to happen after feature expansion,
+     * but before the checks/modifications to ucode_rev, mwait, phys_bits.
+     * These may be set by the accel-specific code,
+     * and the results are subsequently checked / assumed in this function.
+     */
+    cpu_exec_realizefn(cs, &local_err);
+    if (local_err != NULL) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
     x86_cpu_filter_features(cpu, cpu->check_cpuid || cpu->enforce_cpuid);
 
     if (cpu->enforce_cpuid && x86_cpu_have_filtered_features(cpu)) {
@@ -7459,18 +7471,6 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 
     x86_cpu_set_sgxlepubkeyhash(env);
 
-    /*
-     * note: the call to the framework needs to happen after feature expansion,
-     * but before the checks/modifications to ucode_rev, mwait, phys_bits.
-     * These may be set by the accel-specific code,
-     * and the results are subsequently checked / assumed in this function.
-     */
-    cpu_exec_realizefn(cs, &local_err);
-    if (local_err != NULL) {
-        error_propagate(errp, local_err);
-        return;
-    }
-
     if (xcc->host_cpuid_required && !accel_uses_host_cpuid()) {
         g_autofree char *name = x86_cpu_class_get_model_name(xcc);
         error_setg(&local_err, "CPU model '%s' requires KVM or HVF", name);
diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c
index f76972e47e61..3adcedf0dbc3 100644
--- a/target/i386/kvm/kvm-cpu.c
+++ b/target/i386/kvm/kvm-cpu.c
@@ -50,7 +50,6 @@  static bool kvm_cpu_realizefn(CPUState *cs, Error **errp)
      * nothing else has been set by the user (or by accelerators) in
      * cpu->ucode_rev and cpu->phys_bits, and updates the CPUID results in
      * mwait.ecx.
-     * This accel realization code also assumes cpu features are already expanded.
      *
      * realize order:
      *