This patch adds id_reg_info for ID_AA64PFR1_EL1 to make it writable by userspace. Return an error if userspace tries to set MTE field of the register to a value that conflicts with KVM_CAP_ARM_MTE configuration for the guest. Skip fractional feature fields validation at present and they will be handled by the following patches. Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx> --- arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kvm/sys_regs.c | 50 ++++++++++++++++++++++++++------- 2 files changed, 41 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 5c4890cdc29b..e8acc3607590 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -793,6 +793,7 @@ #define ID_AA64PFR0_ELx_32BIT_64BIT 0x2 /* id_aa64pfr1 */ +#define ID_AA64PFR1_CSV2FRAC_SHIFT 32 #define ID_AA64PFR1_MPAMFRAC_SHIFT 16 #define ID_AA64PFR1_RASFRAC_SHIFT 12 #define ID_AA64PFR1_MTE_SHIFT 8 diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c8d31976414a..00ebf4dfc4f8 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -422,6 +422,21 @@ static int validate_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, return 0; } +static int validate_id_aa64pfr1_el1(struct kvm_vcpu *vcpu, + const struct id_reg_info *id_reg, u64 val) +{ + bool kvm_mte = kvm_has_mte(vcpu->kvm); + unsigned int mte; + + mte = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR1_MTE_SHIFT); + + /* Check if there is a conflict with a request via KVM_ARM_VCPU_INIT. */ + if (kvm_mte ^ (mte > 0)) + return -EPERM; + + return 0; +} + static void init_id_aa64pfr0_el1_info(struct id_reg_info *id_reg) { u64 limit = id_reg->vcpu_limit_val; @@ -446,6 +461,12 @@ static void init_id_aa64pfr0_el1_info(struct id_reg_info *id_reg) id_reg->vcpu_limit_val = limit; } +static void init_id_aa64pfr1_el1_info(struct id_reg_info *id_reg) +{ + if (!system_supports_mte()) + id_reg->vcpu_limit_val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE); +} + static u64 get_reset_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, const struct id_reg_info *idr) { @@ -454,6 +475,14 @@ static u64 get_reset_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, (idr->vcpu_limit_val & ~(ARM64_FEATURE_MASK(ID_AA64PFR0_SVE))); } +static u64 get_reset_id_aa64pfr1_el1(struct kvm_vcpu *vcpu, + const struct id_reg_info *idr) +{ + return kvm_has_mte(vcpu->kvm) ? + idr->vcpu_limit_val : + (idr->vcpu_limit_val & ~(ARM64_FEATURE_MASK(ID_AA64PFR1_MTE))); +} + static struct id_reg_info id_aa64pfr0_el1_info = { .sys_reg = SYS_ID_AA64PFR0_EL1, .ftr_check_types = S_FCT(ID_AA64PFR0_ASIMD_SHIFT, FCT_LOWER_SAFE) | @@ -463,6 +492,16 @@ static struct id_reg_info id_aa64pfr0_el1_info = { .get_reset_val = get_reset_id_aa64pfr0_el1, }; +static struct id_reg_info id_aa64pfr1_el1_info = { + .sys_reg = SYS_ID_AA64PFR1_EL1, + .ftr_check_types = U_FCT(ID_AA64PFR1_RASFRAC_SHIFT, FCT_IGNORE) | + U_FCT(ID_AA64PFR1_MPAMFRAC_SHIFT, FCT_IGNORE) | + U_FCT(ID_AA64PFR1_CSV2FRAC_SHIFT, FCT_IGNORE), + .init = init_id_aa64pfr1_el1_info, + .validate = validate_id_aa64pfr1_el1, + .get_reset_val = get_reset_id_aa64pfr1_el1, +}; + /* * An ID register that needs special handling to control the value for the * guest must have its own id_reg_info in id_reg_info_table. @@ -473,6 +512,7 @@ static struct id_reg_info id_aa64pfr0_el1_info = { #define GET_ID_REG_INFO(id) (id_reg_info_table[IDREG_IDX(id)]) static struct id_reg_info *id_reg_info_table[KVM_ARM_ID_REG_MAX_NUM] = { [IDREG_IDX(SYS_ID_AA64PFR0_EL1)] = &id_aa64pfr0_el1_info, + [IDREG_IDX(SYS_ID_AA64PFR1_EL1)] = &id_aa64pfr1_el1_info, }; static int validate_id_reg(struct kvm_vcpu *vcpu, @@ -1307,16 +1347,6 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, u64 val = raz ? 0 : __vcpu_sys_reg(vcpu, IDREG_SYS_IDX(id)); switch (id) { - case SYS_ID_AA64PFR1_EL1: - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE); - if (kvm_has_mte(vcpu->kvm)) { - u64 pfr, mte; - - pfr = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1); - mte = cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR1_MTE_SHIFT); - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR1_MTE), mte); - } - break; case SYS_ID_AA64ISAR1_EL1: if (!vcpu_has_ptrauth(vcpu)) val &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR1_APA) | -- 2.33.1.1089.g2158813163f-goog _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm