[PATCH v2 1/2] i386: Add missing cpu feature bits in EPYC model

["Moger, Babu" <Babu.Moger@amd.com>]

Adds the following missing CPUID bits:
perfctr-core : core performance counter extensions support. Enables the VM
               to use extended performance counter support. It enables six
               programmable counters instead of 4 counters.
clzero       : instruction zeroes out the 64 byte cache line specified in RAX.
xsaveerptr   : XSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES always save error
               pointers and FXRSTOR, XRSTOR, XRSTORS always restore error
               pointers.
ibpb         : Indirect Branch Prediction Barrie.
xsaves       : XSAVES, XRSTORS and IA32_XSS supported.

Depends on following kernel commits:
40bc47b08b6e ("kvm: x86: Enumerate support for CLZERO instruction")
504ce1954fba ("KVM: x86: Expose XSAVEERPTR to the guest")
52297436199d ("kvm: svm: Update svm_xsaves_supported")

These new features will be added in EPYC-v3. The -cpu help output after the change.
x86 EPYC-v1               AMD EPYC Processor
x86 EPYC-v2               AMD EPYC Processor (with IBPB)
x86 EPYC-v3               AMD EPYC Processor

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 target/i386/cpu.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 07cf562d89..6b7b0f8a4b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -3116,10 +3116,6 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_RDSEED |
             CPUID_7_0_EBX_ADX | CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLFLUSHOPT |
             CPUID_7_0_EBX_SHA_NI,
-        /* Missing: XSAVES (not supported by some Linux versions,
-         * including v4.1 to v4.12).
-         * KVM doesn't yet expose any XSAVES state save component.
-         */
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT | CPUID_XSAVE_XSAVEC |
             CPUID_XSAVE_XGETBV1,
@@ -3142,6 +3138,19 @@ static X86CPUDefinition builtin_x86_defs[] = {
                     { /* end of list */ }
                 }
             },
+            {
+                .version = 3,
+                .props = (PropValue[]) {
+                    { "ibpb", "on" },
+                    { "perfctr-core", "on" },
+                    { "clzero", "on" },
+                    { "xsaveerptr", "on" },
+                    { "xsaves", "on" },
+                    { "model-id",
+                      "AMD EPYC Processor" },
+                    { /* end of list */ }
+                }
+            },
             { /* end of list */ }
         }
     },