[RFC,13/22] i386: split hyperv_handle_properties() into hyperv_expand_features()/hyperv_fill_cpuids()

Commit Message

Vitaly Kuznetsov Sept. 4, 2020, 2:54 p.m. UTC

The intention is to call hyperv_expand_features() early, before vCPUs
are created and use the acquired data later when we set guest visible
CPUID data.

Signed-off-by: Vitaly Kuznetsov <[e-mail]>
---
 target/i386/kvm.c | 45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

Patch

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index b7f0e200a75f..c4bb147090a9 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1177,18 +1177,18 @@  static int hv_cpuid_check_and_set(CPUState *cs, struct kvm_cpuid2 *cpuid,
 }
 
 /*
- * Fill in Hyper-V CPUIDs. Returns the number of entries filled in cpuid_ent in
- * case of success, errno < 0 in case of failure and 0 when no Hyper-V
- * extentions are enabled.
+ * Expand Hyper-V CPU features. In partucular, check that all the requested
+ * features are supported by the host and the sanity of the configuration
+ * (that all the required dependencies are included). Also, this takes care
+ * of 'hv_passthrough' mode and fills the environment with all supported
+ * Hyper-V features.
  */
-static int hyperv_handle_properties(CPUState *cs,
-                                    struct kvm_cpuid_entry2 *cpuid_ent)
+static int hyperv_expand_features(CPUState *cs)
 {
     X86CPU *cpu = X86_CPU(cs);
     CPUX86State *env = &cpu->env;
     struct kvm_cpuid2 *cpuid;
     struct kvm_cpuid_entry2 *c;
-    uint32_t cpuid_i = 0;
     int r;
 
     if (!hyperv_enabled(cpu))
@@ -1317,11 +1317,26 @@  static int hyperv_handle_properties(CPUState *cs,
     /* Not exposed by KVM but needed to make CPU hotplug in Windows work */
     env->features[FEAT_HYPERV_EDX] |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;
 
+    g_free(cpuid);
+
     if (r) {
-        r = -ENOSYS;
-        goto free;
+        return -ENOSYS;
     }
 
+    return 0;
+}
+
+/*
+ * Fill in Hyper-V CPUIDs. Returns the number of entries filled in cpuid_ent.
+ */
+static int hyperv_fill_cpuids(CPUState *cs,
+                              struct kvm_cpuid_entry2 *cpuid_ent)
+{
+    X86CPU *cpu = X86_CPU(cs);
+    CPUX86State *env = &cpu->env;
+    struct kvm_cpuid_entry2 *c;
+    uint32_t cpuid_i = 0;
+
     c = &cpuid_ent[cpuid_i++];
     c->function = HV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
     c->eax = hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS) ?
@@ -1382,12 +1397,8 @@  static int hyperv_handle_properties(CPUState *cs,
         c->ecx = env->features[FEAT_HV_NESTED_ECX];
         c->edx = env->features[FEAT_HV_NESTED_EDX];
     }
-    r = cpuid_i;
 
-free:
-    g_free(cpuid);
-
-    return r;
+    return cpuid_i;
 }
 
 static Error *hv_passthrough_mig_blocker;
@@ -1529,11 +1540,13 @@  int kvm_arch_init_vcpu(CPUState *cs)
     env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY;
 
     /* Paravirtualization CPUIDs */
-    r = hyperv_handle_properties(cs, cpuid_data.entries);
+    r = hyperv_expand_features(cs);
     if (r < 0) {
         return r;
-    } else if (r > 0) {
-        cpuid_i = r;
+    }
+
+    if (hyperv_enabled(cpu)) {
+        cpuid_i = hyperv_fill_cpuids(cs, cpuid_data.entries);
         kvm_base = KVM_CPUID_SIGNATURE_NEXT;
         has_msr_hv_hypercall = true;
     }