FEAT_E2H0 is a formalisation of the existing behaviour of HCR_EL2.E2H being programmable to switch between EL2 host mode and the "traditional" nVHE EL2 mode. This implies at some point we might want to model CPUs without FEAT_E2H0 which will always have EL2 host mode enabled.
There are two values to represent no E2H0 systems of which 0b1110 will make HCR_EL2.NV1 RES0 for FEAT_NV systems. For FEAT_NV2 the NV1 bit is always valid. Message-ID: <[email protected]> Signed-off-by: Alex Bennée <[email protected]> Reviewed-by: Mohamed Mediouni <[email protected]> --- v3 - treat E2H0 as a signed field - don't duplicate FEAT_NV check - fold HCR_E2H into wider FEAT_AARCH64 check along with HCR_RW - don't force writable NV1 for FEAT_NV2 v2 - new helper and properly handling NV1 --- docs/system/arm/emulation.rst | 1 + target/arm/cpu-features.h | 15 +++++++++++++++ target/arm/helper.c | 21 +++++++++++++++------ 3 files changed, 31 insertions(+), 6 deletions(-) diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst index e0d5f9886e1..7787691853e 100644 --- a/docs/system/arm/emulation.rst +++ b/docs/system/arm/emulation.rst @@ -54,6 +54,7 @@ the following architecture extensions: - FEAT_DotProd (Advanced SIMD dot product instructions) - FEAT_DoubleFault (Double Fault Extension) - FEAT_E0PD (Preventing EL0 access to halves of address maps) +- FEAT_E2H0 (Programming of HCR_EL2.E2H) - FEAT_EBF16 (AArch64 Extended BFloat16 instructions) - FEAT_ECV (Enhanced Counter Virtualization) - FEAT_EL0 (Support for execution at EL0) diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h index b29e20eeb68..b683c9551a0 100644 --- a/target/arm/cpu-features.h +++ b/target/arm/cpu-features.h @@ -347,6 +347,7 @@ FIELD(ID_AA64MMFR3, ADERR, 56, 4) FIELD(ID_AA64MMFR3, SPEC_FPACC, 60, 4) FIELD(ID_AA64MMFR4, ASID2, 8, 4) +FIELD(ID_AA64MMFR4, E2H0, 24, 4) FIELD(ID_AA64DFR0, DEBUGVER, 0, 4) FIELD(ID_AA64DFR0, TRACEVER, 4, 4) @@ -1378,6 +1379,20 @@ static inline bool isar_feature_aa64_asid2(const ARMISARegisters *id) return FIELD_EX64_IDREG(id, ID_AA64MMFR4, ASID2) != 0; } +/* + * Note the E2H0 ID fields is signed, increasingly negative as more + * isn't implemented. + */ +static inline bool isar_feature_aa64_e2h0(const ARMISARegisters *id) +{ + return FIELD_SEX64_IDREG(id, ID_AA64MMFR4, E2H0) >= 0; +} + +static inline bool isar_feature_aa64_nv1_res0(const ARMISARegisters *id) +{ + return FIELD_SEX64_IDREG(id, ID_AA64MMFR4, E2H0) <= -2; +} + static inline bool isar_feature_aa64_mec(const ARMISARegisters *id) { return FIELD_EX64_IDREG(id, ID_AA64MMFR3, MEC) != 0; diff --git a/target/arm/helper.c b/target/arm/helper.c index 390ea32c218..e12b2455d3f 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -3776,7 +3776,8 @@ static void do_hcr_write(CPUARMState *env, uint64_t value, uint64_t valid_mask) } if (arm_feature(env, ARM_FEATURE_AARCH64)) { - if (cpu_isar_feature(aa64_vh, cpu)) { + if (cpu_isar_feature(aa64_vh, cpu) && + cpu_isar_feature(aa64_e2h0, cpu)) { valid_mask |= HCR_E2H; } if (cpu_isar_feature(aa64_ras, cpu)) { @@ -3801,7 +3802,10 @@ static void do_hcr_write(CPUARMState *env, uint64_t value, uint64_t valid_mask) valid_mask |= HCR_GPF; } if (cpu_isar_feature(aa64_nv, cpu)) { - valid_mask |= HCR_NV | HCR_NV1 | HCR_AT; + valid_mask |= HCR_NV | HCR_AT; + if (!cpu_isar_feature(aa64_nv1_res0, cpu)) { + valid_mask |= HCR_NV1; + } } if (cpu_isar_feature(aa64_nv2, cpu)) { valid_mask |= HCR_NV2; @@ -3817,10 +3821,15 @@ static void do_hcr_write(CPUARMState *env, uint64_t value, uint64_t valid_mask) /* Clear RES0 bits. */ value &= valid_mask; - /* RW is RAO/WI if EL1 is AArch64 only */ - if (arm_feature(env, ARM_FEATURE_AARCH64) && - !cpu_isar_feature(aa64_aa32_el1, cpu)) { - value |= HCR_RW; + if (arm_feature(env, ARM_FEATURE_AARCH64)) { + /* RW is RAO/WI if EL1 is AArch64 only */ + if (!cpu_isar_feature(aa64_aa32_el1, cpu)) { + value |= HCR_RW; + } + /* Strictly E2H is RES1 unless FEAT_E2H0 relaxes the requirement */ + if (!cpu_isar_feature(aa64_e2h0, cpu)) { + value |= HCR_E2H; + } } /* -- 2.47.3
