On Fri, 17 Mar 2023 05:06:34 +0000, Jing Zhang <jingzhangos@xxxxxxxxxx> wrote: > > With per guest ID registers, ID_AA64PFR0_EL1.[CSV2|CSV3] 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 | 2 -- > arch/arm64/kvm/arm.c | 19 +------------------ > arch/arm64/kvm/hyp/nvhe/sys_regs.c | 7 +++---- > arch/arm64/kvm/id_regs.c | 30 ++++++++++++++++++++++-------- > 4 files changed, 26 insertions(+), 32 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index fb6b50b1f111..e926ea91a73c 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -230,8 +230,6 @@ struct kvm_arch { > > cpumask_var_t supported_cpus; > > - u8 pfr0_csv2; > - u8 pfr0_csv3; > struct { > u8 imp:4; > u8 unimp:4; > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 4579c878ab30..c78d68d011cb 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -104,22 +104,6 @@ static int kvm_arm_default_max_vcpus(void) > return vgic_present ? kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS; > } > > -static void set_default_spectre(struct kvm *kvm) > -{ > - /* > - * The default is to expose CSV2 == 1 if the HW isn't affected. > - * Although this is a per-CPU feature, we make it global because > - * asymmetric systems are just a nuisance. > - * > - * Userspace can override this as long as it doesn't promise > - * the impossible. > - */ > - if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) > - kvm->arch.pfr0_csv2 = 1; > - if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) > - kvm->arch.pfr0_csv3 = 1; > -} > - > /** > * kvm_arch_init_vm - initializes a VM data structure > * @kvm: pointer to the KVM struct > @@ -151,9 +135,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > /* The maximum number of VCPUs is limited by the host's GIC model */ > kvm->max_vcpus = kvm_arm_default_max_vcpus(); > > - set_default_spectre(kvm); > - kvm_arm_init_hypercalls(kvm); > kvm_arm_set_default_id_regs(kvm); > + kvm_arm_init_hypercalls(kvm); Please document the ordering dependency between idregs and hypercalls. > > /* > * Initialise the default PMUver before there is a chance to > diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c > index 08d2b004f4b7..0e1988740a65 100644 > --- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c > +++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c > @@ -93,10 +93,9 @@ static u64 get_pvm_id_aa64pfr0(const struct kvm_vcpu *vcpu) > PVM_ID_AA64PFR0_RESTRICT_UNSIGNED); > > /* Spectre and Meltdown mitigation in KVM */ > - set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), > - (u64)kvm->arch.pfr0_csv2); > - set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), > - (u64)kvm->arch.pfr0_csv3); > + set_mask |= vcpu->kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)] & This really want an accessor. > + (ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) | > + ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3)); > > return (id_aa64pfr0_el1_sys_val & allow_mask) | set_mask; > } > diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c > index e393b5730557..b60ca1058301 100644 > --- a/arch/arm64/kvm/id_regs.c > +++ b/arch/arm64/kvm/id_regs.c > @@ -61,12 +61,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id) > if (!vcpu_has_sve(vcpu)) > val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE); > val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU); > - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2); > - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), > - (u64)vcpu->kvm->arch.pfr0_csv2); > - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3); > - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), > - (u64)vcpu->kvm->arch.pfr0_csv3); > if (kvm_vgic_global_state.type == VGIC_V3) { > val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC); > val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1); > @@ -201,6 +195,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, > u64 val) > { > u8 csv2, csv3; > + u64 sval = val; > > /* > * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as > @@ -225,8 +220,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, > if (val) > return -EINVAL; > > - vcpu->kvm->arch.pfr0_csv2 = csv2; > - vcpu->kvm->arch.pfr0_csv3 = csv3; > + vcpu->kvm->arch.id_regs[IDREG_IDX(reg_to_encoding(rd))] = sval; Accessor needed here to. > > return 0; > } > @@ -529,4 +523,24 @@ void kvm_arm_set_default_id_regs(struct kvm *kvm) > val = read_sanitised_ftr_reg(id); > kvm->arch.id_regs[IDREG_IDX(id)] = val; > } > + /* Add a blank line after the closing bracket. > + * The default is to expose CSV2 == 1 if the HW isn't affected. > + * Although this is a per-CPU feature, we make it global because > + * asymmetric systems are just a nuisance. > + * > + * Userspace can override this as long as it doesn't promise > + * the impossible. > + */ > + val = kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)]; Accessor. > + > + if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) { > + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2); > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1); > + } > + if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) { > + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3); > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1); > + } > + > + kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)] = val; Accessor. Thanks, M. -- Without deviation from the norm, progress is not possible.