[PATCH 1/2] i386/cpu: Add the Intel PT capabilities checking before extend the CPUID level

[Luwei Kang]

The current implementation will extend the CPUID level to 0x14 if
Intel PT is enabled in the guest(in x86_cpu_expand_features()) and
the Intel PT will be disabled if it can't pass the capabilities
checking later(in x86_cpu_filter_features()). In this case, the
level of CPUID will be still 0x14 and the CPUID values from leaf
0xe to 0x14 are all zero.

This patch moves the capabilities checking before setting the
level of the CPUID.

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
 target/i386/cpu.c | 63 ++++++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 9eafbe3690..24644abfd4 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6401,12 +6401,40 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error 
**errp)
 
         /* Intel Processor Trace requires CPUID[0x14] */
         if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT)) {
-            if (cpu->intel_pt_auto_level) {
-                x86_cpu_adjust_level(cpu, &cpu->env.cpuid_min_level, 0x14);
-            } else if (cpu->env.cpuid_min_level < 0x14) {
+            uint32_t eax_0, ebx_0, ecx_0, eax_1, ebx_1;
+
+            eax_0 = kvm_arch_get_supported_cpuid(kvm_state, 0x14, 0, R_EAX);
+            ebx_0 = kvm_arch_get_supported_cpuid(kvm_state, 0x14, 0, R_EBX);
+            ecx_0 = kvm_arch_get_supported_cpuid(kvm_state, 0x14, 0, R_ECX);
+            eax_1 = kvm_arch_get_supported_cpuid(kvm_state, 0x14, 1, R_EAX);
+            ebx_1 = kvm_arch_get_supported_cpuid(kvm_state, 0x14, 1, R_EBX);
+
+            if (eax_0 &&
+               ((ebx_0 & INTEL_PT_MINIMAL_EBX) == INTEL_PT_MINIMAL_EBX) &&
+               ((ecx_0 & INTEL_PT_MINIMAL_ECX) == INTEL_PT_MINIMAL_ECX) &&
+               ((eax_1 & INTEL_PT_MTC_BITMAP) == INTEL_PT_MTC_BITMAP) &&
+               ((eax_1 & INTEL_PT_ADDR_RANGES_NUM_MASK) >=
+                                           INTEL_PT_ADDR_RANGES_NUM) &&
+               ((ebx_1 & (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) ==
+                    (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) &&
+               !(ecx_0 & INTEL_PT_IP_LIP)) {
+                if (cpu->intel_pt_auto_level) {
+                    x86_cpu_adjust_level(cpu, &cpu->env.cpuid_min_level, 0x14);
+                } else if (cpu->env.cpuid_min_level < 0x14) {
+                    mark_unavailable_features(cpu, FEAT_7_0_EBX,
+                        CPUID_7_0_EBX_INTEL_PT,
+                        "Intel PT need CPUID leaf 0x14, please set by \"-cpu 
...,+intel-pt,min-level=0x14\"");
+                }
+            } else {
+               /*
+                * Processor Trace capabilities aren't configurable, so if the
+                * host can't emulate the capabilities we report on
+                * cpu_x86_cpuid(), intel-pt can't be enabled on the current
+                * host.
+                */
                 mark_unavailable_features(cpu, FEAT_7_0_EBX,
                     CPUID_7_0_EBX_INTEL_PT,
-                    "Intel PT need CPUID leaf 0x14, please set by \"-cpu 
...,+intel-pt,min-level=0x14\"");
+                    "host Intel PT features doesn't satisfy the guest 
request.");
             }
         }
 
@@ -6466,33 +6494,6 @@ static void x86_cpu_filter_features(X86CPU *cpu, bool 
verbose)
         uint64_t unavailable_features = requested_features & ~host_feat;
         mark_unavailable_features(cpu, w, unavailable_features, prefix);
     }
-
-    if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) &&
-        kvm_enabled()) {
-        KVMState *s = CPU(cpu)->kvm_state;
-        uint32_t eax_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_EAX);
-        uint32_t ebx_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_EBX);
-        uint32_t ecx_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_ECX);
-        uint32_t eax_1 = kvm_arch_get_supported_cpuid(s, 0x14, 1, R_EAX);
-        uint32_t ebx_1 = kvm_arch_get_supported_cpuid(s, 0x14, 1, R_EBX);
-
-        if (!eax_0 ||
-           ((ebx_0 & INTEL_PT_MINIMAL_EBX) != INTEL_PT_MINIMAL_EBX) ||
-           ((ecx_0 & INTEL_PT_MINIMAL_ECX) != INTEL_PT_MINIMAL_ECX) ||
-           ((eax_1 & INTEL_PT_MTC_BITMAP) != INTEL_PT_MTC_BITMAP) ||
-           ((eax_1 & INTEL_PT_ADDR_RANGES_NUM_MASK) <
-                                           INTEL_PT_ADDR_RANGES_NUM) ||
-           ((ebx_1 & (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) !=
-                (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) ||
-           (ecx_0 & INTEL_PT_IP_LIP)) {
-            /*
-             * Processor Trace capabilities aren't configurable, so if the
-             * host can't emulate the capabilities we report on
-             * cpu_x86_cpuid(), intel-pt can't be enabled on the current host.
-             */
-            mark_unavailable_features(cpu, FEAT_7_0_EBX, 
CPUID_7_0_EBX_INTEL_PT, prefix);
-        }
-    }
 }
 
 static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
-- 
2.18.4