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

Marcelo Tosatti
2012-10-09T19:11:47Z

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?

Please provide changelogs for each patch.

> } 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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