Re: [Qemu-devel] [PATCH v6 05/16] target-i386: Use Hypervisor level in -machine pc, accel=kvm.

[Don Slutz <Don@CloudSwitch.Com>]

On 10/09/12 14:47, Marcelo Tosatti wrote:
> On Tue, Oct 09, 2012 at 03:27:26PM -0300, Marcelo Tosatti wrote:
>> On Tue, Oct 09, 2012 at 02:18:05PM -0300, Marcelo Tosatti wrote:
>>> On Mon, Sep 24, 2012 at 10:32:07AM -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 is KVM_CPUID_SIGNATURE (0x40000000).
>>>>
>>>> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
>>>> ---
>>>>   target-i386/kvm.c |    4 ++--
>>>>   1 files changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
>>>> index 895d848..8462c75 100644
>>>> --- a/target-i386/kvm.c
>>>> +++ b/target-i386/kvm.c
>>>> @@ -389,12 +389,12 @@ int kvm_arch_init_vcpu(CPUX86State *env)
>>>>       c = &cpuid_data.entries[cpuid_i++];
>>>>       memset(c, 0, sizeof(*c));
>>>>       c->function = KVM_CPUID_SIGNATURE
>>>> -    if (!hyperv_enabled()) {
>>>> +    if (!env->cpuid_hv_level_set) {
>>>>           memcpy(signature, "KVMKVMKVM\0\0\0", 12);
>>>>           c->eax = 0;
>>>>       } else {
>>>>           memcpy(signature, "Microsoft Hv", 12);
>>>> -        c->eax = HYPERV_CPUID_MIN;
>>>> +        c->eax = env->cpuid_hv_level;
>>> This breaks hyperv_enabled() checks.
>>>
>>> Don, are you certain it is worthwhile to make this configurable?
>>> Can you explain why, under your scenario, it is worthwhile?
>>>
>>> Because these are separate problems:
>>>
>>> - "Fake" VMWare hypervisor  (which seems to be your main goal).
>>> - Make CPUID HV leafs configurable via command line.
>> Err, meant via properties. Point is, why have VMWare CPUID
>> configuration as data, if there are reasons to believe code
>> is a better fit (code as in current Hyper-V implementation).
> Nevermind, its the right thing to do. Just separate the patchset
> please:
>
> 1) Create object properties.
> 2) Export VMWare CPUID via properties.
> 3) Convert Hyper-V.
>
> Be careful to make sure Hyper-V's current options are functional
> in 3).
>
Did you mean 3 patch sets (or more)? Or just a different order?
    -Don Slutz