diff options
| -rw-r--r-- | target/arm/kvm64.c | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c index d16d4ea250..9b9dd46d78 100644 --- a/target/arm/kvm64.c +++ b/target/arm/kvm64.c @@ -507,7 +507,6 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) bool sve_supported; bool pmu_supported = false; uint64_t features = 0; - uint64_t t; int err; /* Old kernels may not know about the PREFERRED_TARGET ioctl: however @@ -528,10 +527,17 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) struct kvm_vcpu_init init = { .target = -1, }; /* - * Ask for Pointer Authentication if supported. We can't play the - * SVE trick of synthesising the ID reg as KVM won't tell us - * whether we have the architected or IMPDEF version of PAuth, so - * we have to use the actual ID regs. + * Ask for SVE if supported, so that we can query ID_AA64ZFR0, + * which is otherwise RAZ. + */ + sve_supported = kvm_arm_sve_supported(); + if (sve_supported) { + init.features[0] |= 1 << KVM_ARM_VCPU_SVE; + } + + /* + * Ask for Pointer Authentication if supported, so that we get + * the unsanitized field values for AA64ISAR1_EL1. */ if (kvm_arm_pauth_supported()) { init.features[0] |= (1 << KVM_ARM_VCPU_PTRAUTH_ADDRESS | @@ -673,25 +679,18 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) err |= read_sys_reg64(fdarray[2], &ahcf->isar.reset_pmcr_el0, ARM64_SYS_REG(3, 3, 9, 12, 0)); } - } - - sve_supported = ioctl(fdarray[0], KVM_CHECK_EXTENSION, KVM_CAP_ARM_SVE) > 0; - /* Add feature bits that can't appear until after VCPU init. */ - if (sve_supported) { - t = ahcf->isar.id_aa64pfr0; - t = FIELD_DP64(t, ID_AA64PFR0, SVE, 1); - ahcf->isar.id_aa64pfr0 = t; - - /* - * There is a range of kernels between kernel commit 73433762fcae - * and f81cb2c3ad41 which have a bug where the kernel doesn't expose - * SYS_ID_AA64ZFR0_EL1 via the ONE_REG API unless the VM has enabled - * SVE support, so we only read it here, rather than together with all - * the other ID registers earlier. - */ - err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64zfr0, - ARM64_SYS_REG(3, 0, 0, 4, 4)); + if (sve_supported) { + /* + * There is a range of kernels between kernel commit 73433762fcae + * and f81cb2c3ad41 which have a bug where the kernel doesn't + * expose SYS_ID_AA64ZFR0_EL1 via the ONE_REG API unless the VM has + * enabled SVE support, which resulted in an error rather than RAZ. + * So only read the register if we set KVM_ARM_VCPU_SVE above. + */ + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64zfr0, + ARM64_SYS_REG(3, 0, 0, 4, 4)); + } } kvm_arm_destroy_scratch_host_vcpu(fdarray); |