Re: [PATCH v2] KVM VMX: Make sure single type invvpid is supported before issuing invvpid instruction

[Sheng Yang <sheng@linux.intel.com>]

On Thursday 03 June 2010 17:45:22 Gui Jianfeng wrote:
> According to SDM, we need check whether single-context INVVPID type is
> supported before issuing invvpid instruction.
> 
> Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> ---
>  arch/x86/include/asm/vmx.h |    2 ++
>  arch/x86/kvm/vmx.c         |   14 +++++++++++++-
>  2 files changed, 15 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index 104cf86..4e78b25 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -376,6 +376,8 @@ enum vmcs_field {
>  #define VMX_EPT_EXTENT_CONTEXT_BIT		(1ull << 25)
>  #define VMX_EPT_EXTENT_GLOBAL_BIT		(1ull << 26)
> 
> +#define VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT      (1ull << 9)
> +
>  #define VMX_EPT_DEFAULT_GAW			3
>  #define VMX_EPT_MAX_GAW				0x4
>  #define VMX_EPT_MT_EPTE_SHIFT			3
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 0e561a5..f363fe3 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -355,6 +355,17 @@ static inline bool cpu_has_vmx_invept_global(void)
>  	return vmx_capability.ept & VMX_EPT_EXTENT_GLOBAL_BIT;
>  }
> 
> +static inline bool cpu_has_vmx_invvpid_single(void)
> +{
> +	/*
> +	 *  bit 41 of IA32_VMX_EPT_VPID_CAP MSR indicates whehter the
> +	 *  single-context INVVPID type is supported. vmx_capability.vpid
> +	 *  represents the higher 32 bits of IA32_VMX_EPT_VPID_CAP MSR, so
> +	 *  VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT(bit 9) is used here.
> +	 */

The comment is better with the VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT marco, since it 
would also applied to other similar ones. 

And I have checked my sent mail, found the word "later" maybe the reason you put 
the comment here... In fact I meant something like

#define VMX_EPT_INVVPID_SINGLE_CONTEXT_BIT (1 << 9) /* (41 - 32) */

Sorry if the word caused confusing...

--
regards
Yang, Sheng

> +	return vmx_capability.vpid & VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT;
> +}
> +
>  static inline bool cpu_has_vmx_ept(void)
>  {
>  	return vmcs_config.cpu_based_2nd_exec_ctrl &
> @@ -499,7 +510,8 @@ static inline void vpid_sync_vcpu_all(struct vcpu_vmx
> *vmx) if (vmx->vpid == 0)
>  		return;
> 
> -	__invvpid(VMX_VPID_EXTENT_SINGLE_CONTEXT, vmx->vpid, 0);
> +	if (cpu_has_vmx_invvpid_single())
> +		__invvpid(VMX_VPID_EXTENT_SINGLE_CONTEXT, vmx->vpid, 0);
>  }
> 
>  static inline void ept_sync_global(void)