Merge remote-tracking branch 'remotes/ehabkost/tags/x86-next-pull-request' into staging

x86 queue, 2019-01-14

* Reenable RDTSCP support on Opteron_G[345] CPU models CPU models
  (Borislav Petkov)
* host-phys-bits-limit option for better control of 5-level EPT
  (Eduardo Habkost)
* Disable MPX support on named CPU models (Paolo Bonzini)
* expose HV_CPUID_ENLIGHTMENT_INFO.EAX and HV_CPUID_NESTED_FEATURES.EAX
  as feature words (Vitaly Kuznetsov)

# gpg: Signature made Mon 14 Jan 2019 14:33:55 GMT
# gpg:                using RSA key 2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/x86-next-pull-request:
  i386/kvm: add a comment explaining why .feat_names are commented out for Hyper-V feature bits
  x86: host-phys-bits-limit option
  target/i386: Disable MPX support on named CPU models
  target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models
  i386/kvm: expose HV_CPUID_ENLIGHTMENT_INFO.EAX and HV_CPUID_NESTED_FEATURES.EAX as feature words

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

5 files changed, 126 insertions, 54 deletions

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index fc65049e1d..73d688f842 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -112,6 +112,16 @@ struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX};
 
 GlobalProperty pc_compat_3_1[] = {
     { "intel-iommu", "dma-drain", "off" },
+    { "Opteron_G3" "-" TYPE_X86_CPU, "rdtscp", "off" },
+    { "Opteron_G4" "-" TYPE_X86_CPU, "rdtscp", "off" },
+    { "Opteron_G5" "-" TYPE_X86_CPU, "rdtscp", "off" },
+    { "Skylake-Client" "-" TYPE_X86_CPU,      "mpx", "on" },
+    { "Skylake-Client-IBRS" "-" TYPE_X86_CPU, "mpx", "on" },
+    { "Skylake-Server" "-" TYPE_X86_CPU,      "mpx", "on" },
+    { "Skylake-Server-IBRS" "-" TYPE_X86_CPU, "mpx", "on" },
+    { "Cascadelake-Server" "-" TYPE_X86_CPU,  "mpx", "on" },
+    { "Icelake-Client" "-" TYPE_X86_CPU,      "mpx", "on" },
+    { "Icelake-Server" "-" TYPE_X86_CPU,      "mpx", "on" },
 };
 const size_t pc_compat_3_1_len = G_N_ELEMENTS(pc_compat_3_1);
 
diff --git a/qemu-doc.texi b/qemu-doc.texi
index f7ad1dfe4b..16b955cbf9 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -37,6 +37,7 @@
 * QEMU System emulator for non PC targets::
 * QEMU Guest Agent::
 * QEMU User space emulator::
+* System requirements::
 * Implementation notes::
 * Deprecated features::
 * Supported build platforms::
@@ -2813,6 +2814,18 @@ Act as if the host page size was 'pagesize' bytes
 Run the emulation in single step mode.
 @end table
 
+@node System requirements
+@chapter System requirements
+
+@section KVM kernel module
+
+On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator
+require the host to be running Linux v4.5 or newer.
+
+The OpteronG[345] CPU models require KVM support for RDTSCP, which was
+added with Linux 4.5 which is supported by the major distros. And even
+if RHEL7 has kernel 3.10, KVM there has the required functionality there
+to make it close to a 4.5 or newer kernel.
 
 @include qemu-tech.texi
 
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index fa37203d89..2f5412592d 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -929,6 +929,13 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
          */
         .no_autoenable_flags = ~0U,
     },
+    /*
+     * .feat_names are commented out for Hyper-V enlightenments because we
+     * don't want to have two different ways for enabling them on QEMU command
+     * line. Some features (e.g. "hyperv_time", "hyperv_vapic", ...) require
+     * enabling several feature bits simultaneously, exposing these bits
+     * individually may just confuse guests.
+     */
     [FEAT_HYPERV_EAX] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
@@ -980,6 +987,36 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         },
         .cpuid = { .eax = 0x40000003, .reg = R_EDX, },
     },
+    [FEAT_HV_RECOMM_EAX] = {
+        .type = CPUID_FEATURE_WORD,
+        .feat_names = {
+            NULL /* hv_recommend_pv_as_switch */,
+            NULL /* hv_recommend_pv_tlbflush_local */,
+            NULL /* hv_recommend_pv_tlbflush_remote */,
+            NULL /* hv_recommend_msr_apic_access */,
+            NULL /* hv_recommend_msr_reset */,
+            NULL /* hv_recommend_relaxed_timing */,
+            NULL /* hv_recommend_dma_remapping */,
+            NULL /* hv_recommend_int_remapping */,
+            NULL /* hv_recommend_x2apic_msrs */,
+            NULL /* hv_recommend_autoeoi_deprecation */,
+            NULL /* hv_recommend_pv_ipi */,
+            NULL /* hv_recommend_ex_hypercalls */,
+            NULL /* hv_hypervisor_is_nested */,
+            NULL /* hv_recommend_int_mbec */,
+            NULL /* hv_recommend_evmcs */,
+            NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+        },
+        .cpuid = { .eax = 0x40000004, .reg = R_EAX, },
+    },
+    [FEAT_HV_NESTED_EAX] = {
+        .type = CPUID_FEATURE_WORD,
+        .cpuid = { .eax = 0x4000000A, .reg = R_EAX, },
+    },
     [FEAT_SVM] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
@@ -2296,7 +2333,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX,
+            CPUID_7_0_EBX_SMAP,
         /* Missing: XSAVES (not supported by some Linux versions,
          * including v4.1 to v4.12).
          * KVM doesn't yet expose any XSAVES state save component,
@@ -2343,7 +2380,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX,
+            CPUID_7_0_EBX_SMAP,
         /* Missing: XSAVES (not supported by some Linux versions,
          * including v4.1 to v4.12).
          * KVM doesn't yet expose any XSAVES state save component,
@@ -2388,7 +2425,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_CLWB |
+            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLWB |
             CPUID_7_0_EBX_AVX512F | CPUID_7_0_EBX_AVX512DQ |
             CPUID_7_0_EBX_AVX512BW | CPUID_7_0_EBX_AVX512CD |
             CPUID_7_0_EBX_AVX512VL | CPUID_7_0_EBX_CLFLUSHOPT,
@@ -2440,7 +2477,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_CLWB |
+            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLWB |
             CPUID_7_0_EBX_AVX512F | CPUID_7_0_EBX_AVX512DQ |
             CPUID_7_0_EBX_AVX512BW | CPUID_7_0_EBX_AVX512CD |
             CPUID_7_0_EBX_AVX512VL,
@@ -2490,7 +2527,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_CLWB |
+            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLWB |
             CPUID_7_0_EBX_AVX512F | CPUID_7_0_EBX_AVX512DQ |
             CPUID_7_0_EBX_AVX512BW | CPUID_7_0_EBX_AVX512CD |
             CPUID_7_0_EBX_AVX512VL | CPUID_7_0_EBX_CLFLUSHOPT |
@@ -2546,7 +2583,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_INTEL_PT,
+            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_INTEL_PT,
         .features[FEAT_7_0_ECX] =
             CPUID_7_0_ECX_VBMI | CPUID_7_0_ECX_UMIP | CPUID_7_0_ECX_PKU |
             CPUID_7_0_ECX_OSPKE | CPUID_7_0_ECX_VBMI2 | CPUID_7_0_ECX_GFNI |
@@ -2601,7 +2638,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_SMEP |
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID |
             CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_RDSEED | CPUID_7_0_EBX_ADX |
-            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_CLWB |
+            CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLWB |
             CPUID_7_0_EBX_AVX512F | CPUID_7_0_EBX_AVX512DQ |
             CPUID_7_0_EBX_AVX512BW | CPUID_7_0_EBX_AVX512CD |
             CPUID_7_0_EBX_AVX512VL | CPUID_7_0_EBX_CLFLUSHOPT |
@@ -2706,7 +2743,6 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_DE | CPUID_FP87,
         .features[FEAT_1_ECX] =
             CPUID_EXT_CX16 | CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,
         .features[FEAT_8000_0001_ECX] =
@@ -2730,9 +2766,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .features[FEAT_1_ECX] =
             CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR |
             CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL |
+            CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A |
             CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM,
@@ -2757,10 +2793,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 |
             CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ |
             CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |
-            CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |
             CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |
@@ -2788,10 +2823,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 |
             CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA |
             CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |
-            CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |
             CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |
@@ -5151,6 +5185,10 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
             if (cpu->host_phys_bits) {
                 /* The user asked for us to use the host physical bits */
                 cpu->phys_bits = host_phys_bits;
+                if (cpu->host_phys_bits_limit &&
+                    cpu->phys_bits > cpu->host_phys_bits_limit) {
+                    cpu->phys_bits = cpu->host_phys_bits_limit;
+                }
             }
 
             /* Print a warning if the user set it to a value that's not the
@@ -5738,6 +5776,7 @@ static Property x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
     DEFINE_PROP_UINT32("phys-bits", X86CPU, phys_bits, 0),
     DEFINE_PROP_BOOL("host-phys-bits", X86CPU, host_phys_bits, false),
+    DEFINE_PROP_UINT8("host-phys-bits-limit", X86CPU, host_phys_bits_limit, 0),
     DEFINE_PROP_BOOL("fill-mtrr-mask", X86CPU, fill_mtrr_mask, true),
     DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, UINT32_MAX),
     DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, UINT32_MAX),
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index ef41a033c5..59656a70e6 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -497,6 +497,8 @@ typedef enum FeatureWord {
     FEAT_HYPERV_EAX,    /* CPUID[4000_0003].EAX */
     FEAT_HYPERV_EBX,    /* CPUID[4000_0003].EBX */
     FEAT_HYPERV_EDX,    /* CPUID[4000_0003].EDX */
+    FEAT_HV_RECOMM_EAX, /* CPUID[4000_0004].EAX */
+    FEAT_HV_NESTED_EAX, /* CPUID[4000_000A].EAX */
     FEAT_SVM,           /* CPUID[8000_000A].EDX */
     FEAT_XSAVE,         /* CPUID[EAX=0xd,ECX=1].EAX */
     FEAT_6_EAX,         /* CPUID[6].EAX */
@@ -1459,6 +1461,9 @@ struct X86CPU {
     /* if true override the phys_bits value with a value read from the host */
     bool host_phys_bits;
 
+    /* if set, limit maximum value for phys_bits when host_phys_bits is true */
+    uint8_t host_phys_bits_limit;
+
     /* Stop SMI delivery for migration compatibility with old machines */
     bool kvm_no_smi_migration;
 
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 739cf8c8ea..9af4542fb8 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -798,6 +798,48 @@ static int hyperv_handle_properties(CPUState *cs)
         }
         env->features[FEAT_HYPERV_EAX] |= HV_SYNTIMERS_AVAILABLE;
     }
+    if (cpu->hyperv_relaxed_timing) {
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_RELAXED_TIMING_RECOMMENDED;
+    }
+    if (cpu->hyperv_vapic) {
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_APIC_ACCESS_RECOMMENDED;
+    }
+    if (cpu->hyperv_tlbflush) {
+        if (kvm_check_extension(cs->kvm_state,
+                                KVM_CAP_HYPERV_TLBFLUSH) <= 0) {
+            fprintf(stderr, "Hyper-V TLB flush support "
+                    "(requested by 'hv-tlbflush' cpu flag) "
+                    " is not supported by kernel\n");
+            return -ENOSYS;
+        }
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_REMOTE_TLB_FLUSH_RECOMMENDED;
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
+    }
+    if (cpu->hyperv_ipi) {
+        if (kvm_check_extension(cs->kvm_state,
+                                KVM_CAP_HYPERV_SEND_IPI) <= 0) {
+            fprintf(stderr, "Hyper-V IPI send support "
+                    "(requested by 'hv-ipi' cpu flag) "
+                    " is not supported by kernel\n");
+            return -ENOSYS;
+        }
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_CLUSTER_IPI_RECOMMENDED;
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
+    }
+    if (cpu->hyperv_evmcs) {
+        uint16_t evmcs_version;
+
+        if (kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_ENLIGHTENED_VMCS, 0,
+                                (uintptr_t)&evmcs_version)) {
+            fprintf(stderr, "Hyper-V Enlightened VMCS "
+                    "(requested by 'hv-evmcs' cpu flag) "
+                    "is not supported by kernel\n");
+            return -ENOSYS;
+        }
+        env->features[FEAT_HV_RECOMM_EAX] |= HV_ENLIGHTENED_VMCS_RECOMMENDED;
+        env->features[FEAT_HV_NESTED_EAX] = evmcs_version;
+    }
+
     return 0;
 }
 
@@ -879,7 +921,6 @@ int kvm_arch_init_vcpu(CPUState *cs)
     uint32_t unused;
     struct kvm_cpuid_entry2 *c;
     uint32_t signature[3];
-    uint16_t evmcs_version;
     int kvm_base = KVM_CPUID_SIGNATURE;
     int r;
     Error *local_err = NULL;
@@ -954,44 +995,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
         c = &cpuid_data.entries[cpuid_i++];
         c->function = HV_CPUID_ENLIGHTMENT_INFO;
-        if (cpu->hyperv_relaxed_timing) {
-            c->eax |= HV_RELAXED_TIMING_RECOMMENDED;
-        }
-        if (cpu->hyperv_vapic) {
-            c->eax |= HV_APIC_ACCESS_RECOMMENDED;
-        }
-        if (cpu->hyperv_tlbflush) {
-            if (kvm_check_extension(cs->kvm_state,
-                                    KVM_CAP_HYPERV_TLBFLUSH) <= 0) {
-                fprintf(stderr, "Hyper-V TLB flush support "
-                        "(requested by 'hv-tlbflush' cpu flag) "
-                        " is not supported by kernel\n");
-                return -ENOSYS;
-            }
-            c->eax |= HV_REMOTE_TLB_FLUSH_RECOMMENDED;
-            c->eax |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
-        }
-        if (cpu->hyperv_ipi) {
-            if (kvm_check_extension(cs->kvm_state,
-                                    KVM_CAP_HYPERV_SEND_IPI) <= 0) {
-                fprintf(stderr, "Hyper-V IPI send support "
-                        "(requested by 'hv-ipi' cpu flag) "
-                        " is not supported by kernel\n");
-                return -ENOSYS;
-            }
-            c->eax |= HV_CLUSTER_IPI_RECOMMENDED;
-            c->eax |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
-        }
-        if (cpu->hyperv_evmcs) {
-            if (kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_ENLIGHTENED_VMCS, 0,
-                                    (uintptr_t)&evmcs_version)) {
-                fprintf(stderr, "Hyper-V Enlightened VMCS "
-                        "(requested by 'hv-evmcs' cpu flag) "
-                        "is not supported by kernel\n");
-                return -ENOSYS;
-            }
-            c->eax |= HV_ENLIGHTENED_VMCS_RECOMMENDED;
-        }
+
+        c->eax = env->features[FEAT_HV_RECOMM_EAX];
         c->ebx = cpu->hyperv_spinlock_attempts;
 
         c = &cpuid_data.entries[cpuid_i++];
@@ -1015,7 +1020,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
             c = &cpuid_data.entries[cpuid_i++];
             c->function = HV_CPUID_NESTED_FEATURES;
-            c->eax = evmcs_version;
+            c->eax = env->features[FEAT_HV_NESTED_EAX];
         }
     }