diff --git a/hw/core/machine.c b/hw/core/machine.c index 0dec48e802..4ff60911e7 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -33,7 +33,9 @@ #include "hw/virtio/virtio-iommu.h" #include "audio/audio.h" -GlobalProperty hw_compat_9_0[] = {}; +GlobalProperty hw_compat_9_0[] = { + {"arm-cpu", "backcompat-cntfrq", "true" }, +}; const size_t hw_compat_9_0_len = G_N_ELEMENTS(hw_compat_9_0); GlobalProperty hw_compat_8_2[] = { diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 9f2ca6633a..fdc3eda318 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -1959,13 +1959,22 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp) if (!cpu->gt_cntfrq_hz) { /* - * 0 means "the board didn't set a value, use the default". - * The default value of the generic timer frequency (as seen in - * CNTFRQ_EL0) is 62.5MHz, which corresponds to a period of 16ns. - * This is what you get (a) for a CONFIG_USER_ONLY CPU (b) if the - * board doesn't set it. + * 0 means "the board didn't set a value, use the default". (We also + * get here for the CONFIG_USER_ONLY case.) + * ARMv8.6 and later CPUs architecturally must use a 1GHz timer; before + * that it was an IMPDEF choice, and QEMU initially picked 62.5MHz, + * which gives a 16ns tick period. + * + * We will use the back-compat value: + * - for QEMU CPU types added before we standardized on 1GHz + * - for versioned machine types with a version of 9.0 or earlier */ - cpu->gt_cntfrq_hz = GTIMER_DEFAULT_HZ; + if (arm_feature(env, ARM_FEATURE_BACKCOMPAT_CNTFRQ) || + cpu->backcompat_cntfrq) { + cpu->gt_cntfrq_hz = GTIMER_BACKCOMPAT_HZ; + } else { + cpu->gt_cntfrq_hz = GTIMER_DEFAULT_HZ; + } } #ifndef CONFIG_USER_ONLY @@ -2574,6 +2583,8 @@ static Property arm_cpu_properties[] = { mp_affinity, ARM64_AFFINITY_INVALID), DEFINE_PROP_INT32("node-id", ARMCPU, node_id, CPU_UNSET_NUMA_NODE_ID), DEFINE_PROP_INT32("core-count", ARMCPU, core_count, -1), + /* True to default to the backward-compat old CNTFRQ rather than 1Ghz */ + DEFINE_PROP_BOOL("backcompat-cntfrq", ARMCPU, backcompat_cntfrq, false), DEFINE_PROP_END_OF_LIST() }; diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 1f90590f93..a550bcd25f 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -956,6 +956,9 @@ struct ArchCPU { */ bool host_cpu_probe_failed; + /* QOM property to indicate we should use the back-compat CNTFRQ default */ + bool backcompat_cntfrq; + /* Specify the number of cores in this CPU cluster. Used for the L2CTLR * register. */ @@ -2373,6 +2376,14 @@ enum arm_features { ARM_FEATURE_M_SECURITY, /* M profile Security Extension */ ARM_FEATURE_M_MAIN, /* M profile Main Extension */ ARM_FEATURE_V8_1M, /* M profile extras only in v8.1M and later */ + /* + * ARM_FEATURE_BACKCOMPAT_CNTFRQ makes the CPU default cntfrq be 62.5MHz + * if the board doesn't set a value, instead of 1GHz. It is for backwards + * compatibility and used only with CPU definitions that were already + * in QEMU before we changed the default. It should not be set on any + * CPU types added in future. + */ + ARM_FEATURE_BACKCOMPAT_CNTFRQ, /* 62.5MHz timer default */ }; static inline int arm_feature(CPUARMState *env, int feature) diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c index 985b1efe16..c15d086049 100644 --- a/target/arm/cpu64.c +++ b/target/arm/cpu64.c @@ -599,6 +599,7 @@ static void aarch64_a57_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -656,6 +657,7 @@ static void aarch64_a53_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); diff --git a/target/arm/internals.h b/target/arm/internals.h index b6c78db024..ee3ebd383e 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -62,9 +62,17 @@ static inline bool excp_is_internal(int excp) /* * Default frequency for the generic timer, in Hz. - * This is 62.5MHz, which gives a 16 ns tick period. + * ARMv8.6 and later CPUs architecturally must use a 1GHz timer; before + * that it was an IMPDEF choice, and QEMU initially picked 62.5MHz, + * which gives a 16ns tick period. + * + * We will use the back-compat value: + * - for QEMU CPU types added before we standardized on 1GHz + * - for versioned machine types with a version of 9.0 or earlier + * In any case, the machine model may override via the cntfrq property. */ -#define GTIMER_DEFAULT_HZ 62500000 +#define GTIMER_DEFAULT_HZ 1000000000 +#define GTIMER_BACKCOMPAT_HZ 62500000 /* Bit definitions for the v7M CONTROL register */ FIELD(V7M_CONTROL, NPRIV, 0, 1) diff --git a/target/arm/tcg/cpu32.c b/target/arm/tcg/cpu32.c index b5a60682fa..bdd82d912a 100644 --- a/target/arm/tcg/cpu32.c +++ b/target/arm/tcg/cpu32.c @@ -457,6 +457,7 @@ static void cortex_a7_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_THUMB2EE); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_DUMMY_C15_REGS); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -505,6 +506,7 @@ static void cortex_a15_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_THUMB2EE); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_DUMMY_C15_REGS); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -696,6 +698,7 @@ static void cortex_r52_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_PMSA); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_AUXCR); cpu->midr = 0x411fd133; /* r1p3 */ @@ -924,6 +927,7 @@ static void arm_max_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); set_feature(&cpu->env, ARM_FEATURE_EL3); diff --git a/target/arm/tcg/cpu64.c b/target/arm/tcg/cpu64.c index 443cffe3a8..da41a44f75 100644 --- a/target/arm/tcg/cpu64.c +++ b/target/arm/tcg/cpu64.c @@ -63,6 +63,7 @@ static void aarch64_a35_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -231,6 +232,7 @@ static void aarch64_a55_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -299,6 +301,7 @@ static void aarch64_a72_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -354,6 +357,7 @@ static void aarch64_a76_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -423,6 +427,7 @@ static void aarch64_a64fx_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_EL2); set_feature(&cpu->env, ARM_FEATURE_EL3); @@ -592,6 +597,7 @@ static void aarch64_neoverse_n1_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -663,6 +669,7 @@ static void aarch64_neoverse_v1_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -885,6 +892,7 @@ static void aarch64_a710_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -982,6 +990,7 @@ static void aarch64_neoverse_n2_initfn(Object *obj) set_feature(&cpu->env, ARM_FEATURE_V8); set_feature(&cpu->env, ARM_FEATURE_NEON); set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER); + set_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); set_feature(&cpu->env, ARM_FEATURE_AARCH64); set_feature(&cpu->env, ARM_FEATURE_CBAR_RO); set_feature(&cpu->env, ARM_FEATURE_EL2); @@ -1077,6 +1086,15 @@ void aarch64_max_tcg_initfn(Object *obj) uint64_t t; uint32_t u; + /* + * Unset ARM_FEATURE_BACKCOMPAT_CNTFRQ, which we would otherwise default + * to because we started with aarch64_a57_initfn(). A 'max' CPU might + * be a v8.6-or-later one, in which case the cntfrq must be 1GHz; and + * because it is our "may change" CPU type we are OK with it not being + * backwards-compatible with how it worked in old QEMU. + */ + unset_feature(&cpu->env, ARM_FEATURE_BACKCOMPAT_CNTFRQ); + /* * Reset MIDR so the guest doesn't mistake our 'max' CPU type for a real * one and try to apply errata workarounds or use impdef features we