[Qemu-devel] [PATCH 3/4] cpu model corrections/updates: support kvm emulated flags

[john cooper]

Add kvm emulated x2apic flag to config defined cpu models
and general support for such hypervisor emulated flags.

In addition to checking user request flags against the host
we also selectively check against kvm for emulated flags.

Signed-off-by: john cooper <address@hidden>
---

diff --git a/hw/pc.c b/hw/pc.c
index 119c110..2a002da 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -849,7 +849,7 @@ static CPUState *pc_new_cpu(const char *cpu_model)
 
     env = cpu_init(cpu_model);
     if (!env) {
-        fprintf(stderr, "Unable to find x86 CPU definition\n");
+        fprintf(stderr, "Unable to support requested x86 CPU definition\n");
         exit(1);
     }
     if ((env->cpuid_features & CPUID_APIC) || smp_cpus > 1) {
diff --git a/sysconfigs/target/target-x86_64.conf 
b/sysconfigs/target/target-x86_64.conf
index 0613870..3b85b2e 100644
--- a/sysconfigs/target/target-x86_64.conf
+++ b/sysconfigs/target/target-x86_64.conf
@@ -8,7 +8,7 @@
    model = "15"
    stepping = "3"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3 ssse3"
+   feature_ecx = "sse3 ssse3 x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx"
    extfeature_ecx = "lahf_lm"
    xlevel = "0x8000000A"
@@ -22,7 +22,7 @@
    model = "23"
    stepping = "3"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3 cx16 ssse3 sse4.1"
+   feature_ecx = "sse3 cx16 ssse3 sse4.1 x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx"
    extfeature_ecx = "lahf_lm"
    xlevel = "0x8000000A"
@@ -36,7 +36,7 @@
    model = "26"
    stepping = "3"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3 cx16 ssse3 sse4.1 sse4.2 popcnt"
+   feature_ecx = "sse3 cx16 ssse3 sse4.1 sse4.2 popcnt x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx"
    extfeature_ecx = "lahf_lm"
    xlevel = "0x8000000A"
@@ -50,7 +50,7 @@
    model = "6"
    stepping = "1"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3"
+   feature_ecx = "sse3 x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx"
 #   extfeature_ecx = ""
    xlevel = "0x80000008"
@@ -64,7 +64,7 @@
    model = "6"
    stepping = "1"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3 cx16"
+   feature_ecx = "sse3 cx16 x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx rdtscp"
    extfeature_ecx = "svm lahf_lm"
    xlevel = "0x80000008"
@@ -78,7 +78,7 @@
    model = "6"
    stepping = "1"
    feature_edx = "sse2 sse fxsr mmx pat cmov pge sep apic cx8 mce pae msr tsc 
pse de fpu    mtrr clflush mca pse36"
-   feature_ecx = "sse3 cx16 monitor popcnt"
+   feature_ecx = "sse3 cx16 monitor popcnt x2apic"
    extfeature_edx = "fxsr mmx pat cmov pge apic cx8 mce pae msr tsc pse de fpu 
   lm syscall nx rdtscp"
    extfeature_ecx = "svm sse4a  abm misalignsse lahf_lm"
    xlevel = "0x80000008"
diff --git a/target-i386/cpuid.c b/target-i386/cpuid.c
index 165045e..c3d0bbb 100644
--- a/target-i386/cpuid.c
+++ b/target-i386/cpuid.c
@@ -548,15 +548,40 @@ static int unavailable_host_feature(struct 
model_features_t *f, uint32_t mask)
     return 0;
 }
 
-/* best effort attempt to inform user requested cpu flags aren't making
- * their way to the guest.  Note: ft[].check_feat ideally should be
- * specified via a guest_def field to suppress report of extraneous flags.
+/* determine the effective set of cpuid features visible to a guest.
+ * in the case kvm is enabled, we also selectively include features
+ * emulated by the hypervisor
+ */ 
+static void summary_cpuid_features(CPUX86State *env, x86_def_t *hd)
+{
+    struct {
+        uint32_t *pfeat, cmd, reg, mask;
+        } fmap[] = {
+            {&hd->features, 0x00000001, R_EDX, 0},
+            {&hd->ext_features, 0x00000001, R_ECX, CPUID_EXT_X2APIC},
+            {&hd->ext2_features, 0x80000001, R_EDX, 0},
+            {&hd->ext3_features, 0x80000001, R_ECX, 0},
+            {NULL}}, *p;
+
+    cpu_x86_fill_host(hd);
+    if (kvm_enabled()) {
+        for (p = fmap; p->pfeat; ++p) {
+            if (p->mask) {
+                *p->pfeat |= p->mask &
+                    kvm_arch_get_supported_cpuid(env, p->cmd, 0, p->reg);
+            }
+        }
+    }
+}
+
+/* inform the user of any requested cpu features (both explicitly requested
+ * flags and implicit cpu model flags) not making their way to the guest
  */
-static int check_features_against_host(x86_def_t *guest_def)
+static int check_features_against_host(CPUX86State *env, x86_def_t *guest_def)
 {
     x86_def_t host_def;
     uint32_t mask;
-    int rv, i;
+    int rv;
     struct model_features_t ft[] = {
         {&guest_def->features, &host_def.features,
             ~0, feature_name, 0x00000000},
@@ -565,16 +590,16 @@ static int check_features_against_host(x86_def_t 
*guest_def)
         {&guest_def->ext2_features, &host_def.ext2_features,
             ~PPRO_FEATURES, ext2_feature_name, 0x80000000},
         {&guest_def->ext3_features, &host_def.ext3_features,
-            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001}};
+            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001},
+        {NULL}}, *p;
 
-    cpu_x86_fill_host(&host_def);
-    for (rv = 0, i = 0; i < ARRAY_SIZE(ft); ++i)
+    summary_cpuid_features(env, &host_def);
+    for (rv = 0, p = ft; p->guest_feat; ++p)
         for (mask = 1; mask; mask <<= 1)
-            if (ft[i].check_feat & mask && *ft[i].guest_feat & mask &&
-                !(*ft[i].host_feat & mask)) {
-                    unavailable_host_feature(&ft[i], mask);
-                    rv = 1;
-                }
+            if (mask & p->check_feat & *p->guest_feat & ~*p->host_feat) {
+                unavailable_host_feature(p, mask);
+                rv = 1;
+            }
     return rv;
 }
 
@@ -601,6 +626,7 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
     if (kvm_enabled() && strcmp(name, "host") == 0) {
         cpu_x86_fill_host(x86_cpu_def);
     } else if (!def) {
+        fprintf(stderr, "Unknown cpu model: %s\n", name);
         goto error;
     } else {
         memcpy(x86_cpu_def, def, sizeof(*def));
@@ -714,10 +740,6 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
     x86_cpu_def->ext3_features &= ~minus_ext3_features;
     x86_cpu_def->kvm_features &= ~minus_kvm_features;
     x86_cpu_def->svm_features &= ~minus_svm_features;
-    if (check_cpuid) {
-        if (check_features_against_host(x86_cpu_def) && enforce_cpuid)
-            goto error;
-    }
     free(s);
     return 0;
 
@@ -880,6 +902,10 @@ int cpu_x86_register (CPUX86State *env, const char 
*cpu_model)
             env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
         }
     }
+    if (check_cpuid) {
+        if (check_features_against_host(env, def) && enforce_cpuid)
+            return -1;
+    }
     return 0;
 }
 
 
-- 
address@hidden