Re: [Xen-devel] [PATCH v5 RESEND 13/17] x86/VPMU: Add privileged PMU mode

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Boris Ostrovsky [mailto:boris.ostrovsky@xxxxxxxxxx]
> Sent: Wednesday, April 23, 2014 8:51 PM
> 
> Add support for privileged PMU mode which allows privileged domain (dom0)
> profile both itself (and the hypervisor) and the guests. While this mode is on
> profiling in guests is disabled.
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> ---
>  xen/arch/x86/hvm/vpmu.c  | 97
> +++++++++++++++++++++++++++++++++---------------
>  xen/arch/x86/traps.c     |  6 ++-
>  xen/include/public/pmu.h |  3 ++
>  3 files changed, 76 insertions(+), 30 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/vpmu.c b/xen/arch/x86/hvm/vpmu.c
> index abc4c1f..dc416f9 100644
> --- a/xen/arch/x86/hvm/vpmu.c
> +++ b/xen/arch/x86/hvm/vpmu.c
> @@ -88,7 +88,8 @@ int vpmu_do_wrmsr(unsigned int msr, uint64_t
> msr_content)
>  {
>      struct vpmu_struct *vpmu = vcpu_vpmu(current);
> 
> -    if ( !(vpmu_mode & XENPMU_MODE_ON) )
> +    if ( (vpmu_mode == XENPMU_MODE_OFF) ||
> +         ((vpmu_mode & XENPMU_MODE_PRIV)
> && !is_control_domain(current->domain)) )
>          return 0;
> 

how about combining above checks into a macro, e.g.

#define vpmu_is_on(mode, vcpu)                  \
        ((mode == XENPMU_MODE_ON) ||    \
        ((mode & XENPMU_MODE_PRIV) && is_control_domain(vcpu->domain)))

Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>

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