[PATCH 1/7] target/i386: disable PerfMonV2 when PERFCORE unavailable

[Dongli Zhang]

When the PERFCORE is disabled with "-cpu host,-perfctr-core", it is
reflected in in guest dmesg.

[    0.285136] Performance Events: AMD PMU driver.

However, the guest cpuid indicates the PerfMonV2 is still available.

CPU:
   Extended Performance Monitoring and Debugging (0x80000022):
      AMD performance monitoring V2         = true
      AMD LBR V2                            = false
      AMD LBR stack & PMC freezing          = false
      number of core perf ctrs              = 0x6 (6)
      number of LBR stack entries           = 0x0 (0)
      number of avail Northbridge perf ctrs = 0x0 (0)
      number of available UMC PMCs          = 0x0 (0)
      active UMCs bitmask                   = 0x0

Disable PerfMonV2 in cpuid when PERFCORE is disabled.

Fixes: 209b0ac12074 ("target/i386: Add PerfMonV2 feature bit")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
 target/i386/cpu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3baa95481f..4490a7a8d6 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7103,6 +7103,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
         *eax = *ebx = *ecx = *edx = 0;
         /* AMD Extended Performance Monitoring and Debug */
         if (kvm_enabled() && cpu->enable_pmu &&
+            (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_PERFCORE) &&
             (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,
-- 
2.39.3