Re: [PATCH v6 06/16] target-i386: Use Hypervisor level in -machine pc,accel=tcg.

Don Slutz
2012-10-10T13:07:19Z

On 10/09/12 15:01, Marcelo Tosatti wrote:
> On Mon, Sep 24, 2012 at 10:32:08AM -0400, Don Slutz wrote:
>> Also known as Paravirtualization level.
>>
>> 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
>>
>> QEMU knows this as KVM_CPUID_SIGNATURE (0x40000000) in kvm on linux.
>>
>> This does not provide vendor support in tcg yet.
>>
>> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
>> ---
>> target-i386/cpu.c | 27 +++++++++++++++++++++++++++
>> 1 files changed, 27 insertions(+), 0 deletions(-)
>>
>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>> index 48bdaf9..920278b 100644
>> --- a/target-i386/cpu.c
>> +++ b/target-i386/cpu.c
>> @@ -1651,6 +1651,21 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
>> index = env->cpuid_xlevel;
>> }
>> }
>> + } else if (index & 0x40000000) {
>> + if (env->cpuid_hv_level_set) {
>> + uint32_t real_level = env->cpuid_hv_level;
>> +
>> + /* Handle Hypervisor CPUIDs */
>> + if (real_level < 0x40000000) {
>> + real_level = 0x40000000;
>> + }
>> + if (index > real_level) {
>> + index = real_level;
>> + }
>> + } else {
>> + if (index > env->cpuid_level)
>> + index = env->cpuid_level;
>> + }
> Whats the purpose of this checks?
They control what happens for CPUID requests outside the defined
ranges. Very similar to code just above this.
>
> Please provide changelogs for each patch.
In progress.
>> } else {
>> if (index > env->cpuid_level)
>> index = env->cpuid_level;
>> @@ -1789,6 +1804,18 @@ 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
>>
>> --
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-Don Slutz