Hi Reiji, On Tue, Apr 18, 2023 at 8:40 PM Reiji Watanabe <reijiw@xxxxxxxxxx> wrote: > > Hi Jing, > > On Tue, Apr 04, 2023 at 03:53:42AM +0000, Jing Zhang 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 | 50 ++++++++++++++++++++++++------- > > include/kvm/arm_pmu.h | 5 ++-- > > 4 files changed, 49 insertions(+), 23 deletions(-) > > > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > > index 67a55177fd83..da46a2729581 100644 > > --- a/arch/arm64/include/asm/kvm_host.h > > +++ b/arch/arm64/include/asm/kvm_host.h > > @@ -237,6 +237,12 @@ 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; > > > > @@ -249,11 +255,6 @@ 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 64e1c19e5a9b..3fe28d545b54 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_init_hypercalls(kvm); > > kvm_arm_init_id_regs(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 291311b1ecca..6f65d30693fe 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 FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), > > + IDREG(vcpu->kvm, 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; > > > > - return vcpu->kvm->arch.dfr0_pmuver.unimp; > > + return 0; > > } > > > > static u8 perfmon_to_pmuver(u8 perfmon) > > @@ -254,10 +257,20 @@ 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->arch.config_lock); > > + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ID_AA64DFR0_EL1_PMUVer_MASK; > > + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, > > + pmuver); > > + > > + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ID_DFR0_EL1_PerfMon_MASK; > > + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, > > + pmuver_to_perfmon(pmuver)); > > As those could be read without acquiring the lock, I don't think > we should expose the intermediate state of the register values. I will protect all reads/writes to KVM scope emulated ID registers with the lock. > > > > + mutex_unlock(&vcpu->kvm->arch.config_lock); > > + } else { > > + assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, > > + pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF); > > + } > > > > return 0; > > } > > @@ -294,10 +307,19 @@ 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->arch.config_lock); > > + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ID_DFR0_EL1_PerfMon_MASK; > > + IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon); > > + > > + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ID_AA64DFR0_EL1_PMUVer_MASK; > > + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, > > + perfmon_to_pmuver(perfmon)); > > I have the same comment as set_id_aa64dfr0_el1(). > > Thank you, > Reiji > > > + mutex_unlock(&vcpu->kvm->arch.config_lock); > > + } else { > > + assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags, > > + perfmon == ID_DFR0_EL1_PerfMon_IMPDEF); > > + } > > > > return 0; > > } > > @@ -503,4 +525,12 @@ void kvm_arm_init_id_regs(struct kvm *kvm) > > } > > > > IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val; > > + > > + /* > > + * Initialise the default PMUver before there is a chance to > > + * create an actual PMU. > > + */ > > + IDREG(kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer); > > + IDREG(kvm, SYS_ID_AA64DFR0_EL1) |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), > > + kvm_arm_pmu_get_pmuver_limit()); > > } > > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h > > index 628775334d5e..856ac59b6821 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), \ > > + IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1)) >= ID_AA64DFR0_EL1_PMUVer_V3P5) > > > > u8 kvm_arm_pmu_get_pmuver_limit(void); > > > > -- > > 2.40.0.348.gf938b09366-goog > > Thanks, Jing