[Qemu-devel] [PATCH v7 15/17] target-i386: Use Hypervisor level in -machine pc, accel=tcg.

[Don Slutz <Don@CloudSwitch.com>]

Part of "target-i386: Add way to expose VMWare CPUID"

Also known as Paravirtualization level.

QEMU knows this as KVM_CPUID_SIGNATURE (0x40000000) in kvm on linux.

This does not provide vendor support in tcg yet.

>From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
kvm has this issue:

"Note also that old hosts set eax value to 0x0. This should
be interpreted as if the value was 0x40000001."

This change is based on:

Microsoft Hypervisor CPUID Leaves:
  http://msdn.microsoft.com/en-us/library/windows/hardware/ff542428%28v=vs.85%29.aspx

Linux kernel change starts with:
  http://fixunix.com/kernel/538707-use-cpuid-communicate-hypervisor.html
Also:
  http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html

VMware documention on CPUIDs (Mechanisms to determine if software is
running in a VMware virtual machine):
  http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458

Signed-off-by: Don Slutz <Don@CloudSwitch.com>
---
 target-i386/cpu.c |   30 ++++++++++++++++++++++++++++++
 1 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index c8466ec..5b33b95 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1767,6 +1767,24 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 index =  env->cpuid_xlevel;
             }
         }
+    } else if (index & 0x40000000) {
+        /* test if maximum index reached
+         * but only if Hypervisor level is set */
+        if (env->cpuid_hv_level_set) {
+            uint32_t real_level = env->cpuid_hv_level;
+
+            /* Handle Hypervisor CPUIDs.
+             * kvm defines 0 to be the same as 0x40000001 */
+            if (real_level < 0x40000000) {
+                real_level = 0x40000001;
+            }
+            if (index > real_level) {
+                index = real_level;
+            }
+        } else {
+            if (index > env->cpuid_level)
+                index = env->cpuid_level;
+        }
     } else {
         if (index > env->cpuid_level)
             index = env->cpuid_level;
@@ -1905,6 +1923,18 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             *edx = 0;
         }
         break;
+    case 0x40000000:
+        *eax = env->cpuid_hv_level;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        break;
+    case 0x40000001:
+        *eax = env->cpuid_kvm_features;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        break;
     case 0x80000000:
         *eax = env->cpuid_xlevel;
         *ebx = env->cpuid_vendor1;
-- 
1.7.1