[PATCH v4 2/6] target/i386: Gate enable_pmu on kvm_enabled()

[Zide Chen <zide.chen@intel.com>]

Guest PMU support requires KVM.  Clear cpu->enable_pmu when KVM is not
enabled, so PMU-related code can rely solely on cpu->enable_pmu.

This reduces duplication and avoids bugs where one of the checks is
missed.  For example, cpu_x86_cpuid() enables CPUID.0AH when
cpu->enable_pmu is set but does not check kvm_enabled(). This is
implicitly fixed by this patch:

if (cpu->enable_pmu) {
	x86_cpu_get_supported_cpuid(0xA, count, eax, ebx, ecx, edx);
}

Also fix two places that check kvm_enabled() but not cpu->enable_pmu.

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
V2:
- Replace a tab with spaces.
---
 target/i386/cpu.c     | 10 +++++++---
 target/i386/kvm/kvm.c |  4 ++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index b5e483e8cd25..c978e957df6a 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -8790,7 +8790,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         *ecx = 0;
         *edx = 0;
         if (!(env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) ||
-            !kvm_enabled()) {
+            !cpu->enable_pmu) {
             break;
         }
 
@@ -9137,7 +9137,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
     case 0x80000022:
         *eax = *ebx = *ecx = *edx = 0;
         /* AMD Extended Performance Monitoring and Debug */
-        if (kvm_enabled() && cpu->enable_pmu &&
+        if (cpu->enable_pmu &&
             (env->features[FEAT_8000_0022_EAX] & CPUID_8000_0022_EAX_PERFMON_V2)) {
             *eax |= CPUID_8000_0022_EAX_PERFMON_V2;
             *ebx |= kvm_arch_get_supported_cpuid(cs->kvm_state, index, count,
@@ -9753,7 +9753,7 @@ static bool x86_cpu_filter_features(X86CPU *cpu, bool verbose)
      * are advertised by cpu_x86_cpuid().  Keep these two in sync.
      */
     if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) &&
-        kvm_enabled()) {
+        cpu->enable_pmu) {
         x86_cpu_get_supported_cpuid(0x14, 0,
                                     &eax_0, &ebx_0, &ecx_0, &edx_0);
         x86_cpu_get_supported_cpuid(0x14, 1,
@@ -9901,6 +9901,10 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
     Error *local_err = NULL;
     unsigned requested_lbr_fmt;
 
+    if (!kvm_enabled()) {
+        cpu->enable_pmu = false;
+    }
+
 #if defined(CONFIG_TCG) && !defined(CONFIG_USER_ONLY)
     /* Use pc-relative instructions in system-mode */
     tcg_cflags_set(cs, CF_PCREL);
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 1ac1803e8a2e..5c953a0f3a60 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -4483,7 +4483,7 @@ static int kvm_put_msrs(X86CPU *cpu, KvmPutState level)
                               env->msr_xfd_err);
         }
 
-        if (kvm_enabled() && cpu->enable_pmu &&
+        if (cpu->enable_pmu &&
             (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR)) {
             uint64_t depth;
             int ret;
@@ -4995,7 +4995,7 @@ static int kvm_get_msrs(X86CPU *cpu)
         kvm_msr_entry_add(cpu, MSR_IA32_XFD_ERR, 0);
     }
 
-    if (kvm_enabled() && cpu->enable_pmu &&
+    if (cpu->enable_pmu &&
         (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR)) {
         uint64_t depth;
 
-- 
2.54.0