Hi Marc,
On Mon, Mar 27, 2023 at 3:40 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> On Fri, 17 Mar 2023 05:06:35 +0000,
> Jing Zhang <jingzhangos@xxxxxxxxxx> wrote:
> >
> > With per guest ID registers, PMUver settings from userspace
> > can be stored in its corresponding ID register.
> >
> > No functional change intended.
> >
> > Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
> > ---
> > arch/arm64/include/asm/kvm_host.h | 11 +++---
> > arch/arm64/kvm/arm.c | 6 ---
> > arch/arm64/kvm/id_regs.c | 61 +++++++++++++++++++++++++------
> > include/kvm/arm_pmu.h | 5 ++-
> > 4 files changed, 59 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> > index e926ea91a73c..102860ba896d 100644
> > --- a/arch/arm64/include/asm/kvm_host.h
> > +++ b/arch/arm64/include/asm/kvm_host.h
> > @@ -218,6 +218,12 @@ struct kvm_arch {
> > #define KVM_ARCH_FLAG_EL1_32BIT 4
> > /* PSCI SYSTEM_SUSPEND enabled for the guest */
> > #define KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED 5
> > + /*
> > + * AA64DFR0_EL1.PMUver was set as ID_AA64DFR0_EL1_PMUVer_IMP_DEF
> > + * or DFR0_EL1.PerfMon was set as ID_DFR0_EL1_PerfMon_IMPDEF from
> > + * userspace for VCPUs without PMU.
> > + */
> > +#define KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU 6
> >
> > unsigned long flags;
> >
> > @@ -230,11 +236,6 @@ struct kvm_arch {
> >
> > cpumask_var_t supported_cpus;
> >
> > - struct {
> > - u8 imp:4;
> > - u8 unimp:4;
> > - } dfr0_pmuver;
> > -
> > /* Hypercall features firmware registers' descriptor */
> > struct kvm_smccc_features smccc_feat;
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index c78d68d011cb..fb2de2cb98cb 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -138,12 +138,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> > kvm_arm_set_default_id_regs(kvm);
> > kvm_arm_init_hypercalls(kvm);
> >
> > - /*
> > - * Initialise the default PMUver before there is a chance to
> > - * create an actual PMU.
> > - */
> > - kvm->arch.dfr0_pmuver.imp = kvm_arm_pmu_get_pmuver_limit();
> > -
> > return 0;
> >
> > err_free_cpumask:
> > diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
> > index b60ca1058301..3a87a3d2390d 100644
> > --- a/arch/arm64/kvm/id_regs.c
> > +++ b/arch/arm64/kvm/id_regs.c
> > @@ -21,9 +21,12 @@
> > static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
> > {
> > if (kvm_vcpu_has_pmu(vcpu))
> > - return vcpu->kvm->arch.dfr0_pmuver.imp;
> > -
> > - return vcpu->kvm->arch.dfr0_pmuver.unimp;
> > + return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)]);
> > + else if (test_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags))
> > + return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
> > + else
> > + return 0;
>
> Drop the pointless elses.
Will do.
>
> > }
> >
> > static u8 perfmon_to_pmuver(u8 perfmon)
> > @@ -256,10 +259,23 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> > if (val)
> > return -EINVAL;
> >
> > - if (valid_pmu)
> > - vcpu->kvm->arch.dfr0_pmuver.imp = pmuver;
> > - else
> > - vcpu->kvm->arch.dfr0_pmuver.unimp = pmuver;
> > + if (valid_pmu) {
> > + mutex_lock(&vcpu->kvm->lock);
>
> Bingo!
>
Will fix it.
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] &=
> > + ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] |=
> > + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), pmuver);
> > +
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_DFR0_EL1)] &=
> > + ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_DFR0_EL1)] |= FIELD_PREP(
> > + ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), pmuver_to_perfmon(pmuver));
> > + mutex_unlock(&vcpu->kvm->lock);
> > + } else if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) {
> > + set_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags);
> > + } else {
> > + clear_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags);
> > + }
>
> The last two cases are better written as:
>
> assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
> pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
>
Will do.
> >
> > return 0;
> > }
> > @@ -296,10 +312,23 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
> > if (val)
> > return -EINVAL;
> >
> > - if (valid_pmu)
> > - vcpu->kvm->arch.dfr0_pmuver.imp = perfmon_to_pmuver(perfmon);
> > - else
> > - vcpu->kvm->arch.dfr0_pmuver.unimp = perfmon_to_pmuver(perfmon);
> > + if (valid_pmu) {
> > + mutex_lock(&vcpu->kvm->lock);
>
> Same here (lock inversion)
Will fix it.
>
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_DFR0_EL1)] &=
> > + ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_DFR0_EL1)] |= FIELD_PREP(
> > + ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), perfmon);
> > +
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] &=
> > + ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] |= FIELD_PREP(
> > + ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), perfmon_to_pmuver(perfmon));
> > + mutex_unlock(&vcpu->kvm->lock);
> > + } else if (perfmon == ID_DFR0_EL1_PerfMon_IMPDEF) {
> > + set_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags);
> > + } else {
> > + clear_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags);
> > + }
>
> Same here (assign_bit).
Will do.
> >
> > return 0;
> > }
> > @@ -543,4 +572,14 @@ void kvm_arm_set_default_id_regs(struct kvm *kvm)
> > }
> >
> > kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)] = val;
> > +
> > + /*
> > + * Initialise the default PMUver before there is a chance to
> > + * create an actual PMU.
> > + */
> > + kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] &=
> > + ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > + kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)] |=
> > + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> > + kvm_arm_pmu_get_pmuver_limit());
>
> Please put these assignments on a single line...
Will do.
>
> > }
> > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> > index 628775334d5e..51c7f3e7bdde 100644
> > --- a/include/kvm/arm_pmu.h
> > +++ b/include/kvm/arm_pmu.h
> > @@ -92,8 +92,9 @@ void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
> > /*
> > * Evaluates as true when emulating PMUv3p5, and false otherwise.
> > */
> > -#define kvm_pmu_is_3p5(vcpu) \
> > - (vcpu->kvm->arch.dfr0_pmuver.imp >= ID_AA64DFR0_EL1_PMUVer_V3P5)
> > +#define kvm_pmu_is_3p5(vcpu) \
> > + (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), \
> > + vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64DFR0_EL1)]) >= ID_AA64DFR0_EL1_PMUVer_V3P5)
>
> I'll stop mentioning the need for accessors...
Will fix it.
>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
Thanks,
Jing
