Re: [PATCH v2] KVM: x86/pmu: Manipulate FIXED_CTR_CTRL MSR with macros

[Mi, Dapeng]

On 8/21/2023 4:05 PM, Like Xu wrote:
> On 15/8/2023 11:28 am, Dapeng Mi wrote:
> > Magic numbers are used to manipulate the bit fields of
> > FIXED_CTR_CTRL MSR. This is not read-friendly and use macros to replace
> > these magic numbers to increase the readability.
>
> More, reuse INTEL_FIXED_0_* macros for pmu->fixed_ctr_ctrl_mask, pls.

Sure. Thanks.
> > Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
> > ---
> >   arch/x86/kvm/pmu.c | 10 +++++-----
> >   arch/x86/kvm/pmu.h |  6 ++++--
> >   2 files changed, 9 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> > index edb89b51b383..fb4ef2da3e32 100644
> > --- a/arch/x86/kvm/pmu.c
> > +++ b/arch/x86/kvm/pmu.c
> > @@ -420,11 +420,11 @@ static void reprogram_counter(struct kvm_pmc *pmc)
> >       if (pmc_is_fixed(pmc)) {
> >           fixed_ctr_ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl,
> >                             pmc->idx - INTEL_PMC_IDX_FIXED);
> > -        if (fixed_ctr_ctrl & 0x1)
> > +        if (fixed_ctr_ctrl & INTEL_FIXED_0_KERNEL)
> >               eventsel |= ARCH_PERFMON_EVENTSEL_OS;
> > -        if (fixed_ctr_ctrl & 0x2)
> > +        if (fixed_ctr_ctrl & INTEL_FIXED_0_USER)
> >               eventsel |= ARCH_PERFMON_EVENTSEL_USR;
> > -        if (fixed_ctr_ctrl & 0x8)
> > +        if (fixed_ctr_ctrl & INTEL_FIXED_0_ENABLE_PMI)
> >               eventsel |= ARCH_PERFMON_EVENTSEL_INT;
> >           new_config = (u64)fixed_ctr_ctrl;
> >       }
> > @@ -749,8 +749,8 @@ static inline bool cpl_is_matched(struct kvm_pmc 
> > *pmc)
> >       } else {
> >           config = fixed_ctrl_field(pmc_to_pmu(pmc)->fixed_ctr_ctrl,
> >                         pmc->idx - INTEL_PMC_IDX_FIXED);
> > -        select_os = config & 0x1;
> > -        select_user = config & 0x2;
> > +        select_os = config & INTEL_FIXED_0_KERNEL;
> > +        select_user = config & INTEL_FIXED_0_USER;
> >       }
> >         return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? 
> > select_os : select_user;
> > diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
> > index 7d9ba301c090..ffda2ecc3a22 100644
> > --- a/arch/x86/kvm/pmu.h
> > +++ b/arch/x86/kvm/pmu.h
> > @@ -12,7 +12,8 @@
> >                         MSR_IA32_MISC_ENABLE_BTS_UNAVAIL)
> >     /* retrieve the 4 bits for EN and PMI out of IA32_FIXED_CTR_CTRL */
> > -#define fixed_ctrl_field(ctrl_reg, idx) (((ctrl_reg) >> ((idx)*4)) & 
> > 0xf)
> > +#define fixed_ctrl_field(ctrl_reg, idx) \
> > +    (((ctrl_reg) >> ((idx) * INTEL_FIXED_BITS_STRIDE)) & 
> > INTEL_FIXED_BITS_MASK)
> >     #define VMWARE_BACKDOOR_PMC_HOST_TSC        0x10000
> >   #define VMWARE_BACKDOOR_PMC_REAL_TIME        0x10001
> > @@ -165,7 +166,8 @@ static inline bool pmc_speculative_in_use(struct 
> > kvm_pmc *pmc)
> >         if (pmc_is_fixed(pmc))
> >           return fixed_ctrl_field(pmu->fixed_ctr_ctrl,
> > -                    pmc->idx - INTEL_PMC_IDX_FIXED) & 0x3;
> > +                    pmc->idx - INTEL_PMC_IDX_FIXED) &
> > +                    (INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER);
> >         return pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE;
> >   }
> >
> > base-commit: 240f736891887939571854bd6d734b6c9291f22e