The max cpu type can have its SVE vector lengths explicitly set with the sve-vls-map property. This patch allows that property to work when KVM is in use. The map must conform to additional constraints for KVM which are checked at vcpu init.
Signed-off-by: Andrew Jones <drjo...@redhat.com> --- target/arm/cpu64.c | 7 +++--- target/arm/kvm64.c | 56 +++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 56 insertions(+), 7 deletions(-) diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c index 9ac702d54136..94f3dd5b51e5 100644 --- a/target/arm/cpu64.c +++ b/target/arm/cpu64.c @@ -310,7 +310,7 @@ static void cpu_set_sve_vls_map(Object *obj, Visitor *v, const char *name, error_setg(&err, "SVE vector length map has unsupported lengths"); error_append_hint(&err, "Valid vector lengths in range [1-%d]\n", ARM_MAX_VQ); - } else if (cpu->sve_max_vq != ARM_MAX_VQ && + } else if (cpu->sve_max_vq != ARM_MAX_VQ && cpu->sve_max_vq != -1 && cpu->sve_max_vq != arm_cpu_fls64(cpu->sve_vls_map)) { /* * If the user provides both sve-max-vq and sve-vls-map, with @@ -433,13 +433,12 @@ static void aarch64_max_initfn(Object *obj) #endif cpu->sve_max_vq = ARM_MAX_VQ; - - object_property_add(obj, "sve-vls-map", "uint64", cpu_get_sve_vls_map, - cpu_set_sve_vls_map, NULL, NULL, &error_fatal); } object_property_add(obj, "sve-max-vq", "uint32", cpu_max_get_sve_vq, cpu_max_set_sve_vq, NULL, NULL, &error_fatal); + object_property_add(obj, "sve-vls-map", "uint64", cpu_get_sve_vls_map, + cpu_set_sve_vls_map, NULL, NULL, &error_fatal); } struct ARMCPUInfo { diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c index 11c6334a7c08..5506f019c190 100644 --- a/target/arm/kvm64.c +++ b/target/arm/kvm64.c @@ -685,9 +685,9 @@ int kvm_arch_init_vcpu(CPUState *cs) } else { unset_feature(&env->features, ARM_FEATURE_PMU); } - if (cpu->sve_max_vq) { + if (cpu->sve_max_vq || cpu->sve_vls_map) { if (!kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_SVE)) { - if (cpu->sve_max_vq == -1) { + if (cpu->sve_max_vq == -1 && !cpu->sve_vls_map) { cpu->sve_max_vq = 0; } else { error_report("This KVM host does not support SVE"); @@ -704,12 +704,62 @@ int kvm_arch_init_vcpu(CPUState *cs) return ret; } - if (cpu->sve_max_vq) { + if (cpu->sve_max_vq || cpu->sve_vls_map) { uint64_t sve_vls[KVM_ARM64_SVE_VLS_WORDS]; ret = kvm_arm_get_sve_vls(cs, sve_vls); if (ret < 0) { return ret; } + if (cpu->sve_vls_map) { + uint64_t ovls; + int i; + + /* + * We currently only support a single VLS word, as that should + * be sufficient for some time (vq=64 means a 8192-bit vector + * and KVM currently only supports up to 2048-bit vectors). + * The choice to only support a single word for now is due to + * the need to input it on the command line. It's much simpler + * to input a word as a cpu property than an array of words. + * So for now just warn if we detect our assumption was wrong. + */ + for (i = 1; i < KVM_ARM64_SVE_VLS_WORDS; ++i) { + if (sve_vls[i]) { + warn_report("KVM supports vector lengths larger than " + "sve-vls-map can select"); + sve_vls[i] = 0; + } + } + + ovls = sve_vls[0]; + sve_vls[0] = cpu->sve_vls_map; + + if (cpu->sve_vls_map & ~ovls) { + error_report("sve-vls-map=0x%lx is not valid on this host " + "which supports 0x%lx", cpu->sve_vls_map, ovls); + return -EINVAL; + } + + i = arm_cpu_fls64(cpu->sve_vls_map); + if (cpu->sve_max_vq && cpu->sve_max_vq != -1 && + cpu->sve_max_vq != i) { + error_report("sve-vls-map and sve-max-vq are inconsistent"); + return -EINVAL; + } + cpu->sve_max_vq = i; + + /* + * sve-vls-map must have all the same vector lengths up to its + * max vq that the host supports. + */ + if (cpu->sve_vls_map != (ovls & (BIT_MASK(cpu->sve_max_vq) - 1))) { + error_report("sve-vls-map=0x%lx is not valid on this host " + "which supports 0x%lx", cpu->sve_vls_map, ovls); + error_printf("All host vector lengths up to %d must also " + "be selected.\n", cpu->sve_max_vq); + return -EINVAL; + } + } if (cpu->sve_max_vq == -1) { cpu->sve_max_vq = ret; } else if (cpu->sve_max_vq > ret) { -- 2.20.1