Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- target/arm/kvm64.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 67 insertions(+), 2 deletions(-)
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c index 5de8ff0ac5..d4d4e63140 100644 --- a/target/arm/kvm64.c +++ b/target/arm/kvm64.c @@ -443,17 +443,40 @@ static inline void unset_feature(uint64_t *features, int feature) *features &= ~(1ULL << feature); } +static int read_sys_reg32(int fd, uint32_t *pret, uint64_t id) +{ + uint64_t ret; + struct kvm_one_reg idreg = { .id = id, .addr = (uintptr_t)&ret }; + int err; + + assert((id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64); + err = ioctl(fd, KVM_GET_ONE_REG, &idreg); + if (err < 0) { + return -1; + } + *pret = ret; + return 0; +} + +static int read_sys_reg64(int fd, uint64_t *pret, uint64_t id) +{ + struct kvm_one_reg idreg = { .id = id, .addr = (uintptr_t)pret }; + + assert((id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64); + return ioctl(fd, KVM_GET_ONE_REG, &idreg); +} + bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) { /* Identify the feature bits corresponding to the host CPU, and * fill out the ARMHostCPUClass fields accordingly. To do this * we have to create a scratch VM, create a single CPU inside it, * and then query that CPU for the relevant ID registers. - * For AArch64 we currently don't care about ID registers at - * all; we just want to know the CPU type. */ int fdarray[3]; uint64_t features = 0; + int err = 0; + /* Old kernels may not know about the PREFERRED_TARGET ioctl: however * we know these will only support creating one kind of guest CPU, * which is its preferred CPU type. Fortunately these old kernels @@ -474,8 +497,50 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) ahcf->target = init.target; ahcf->dtb_compatible = "arm,arm-v8"; + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar0, + ARM64_SYS_REG(3, 0, 0, 6, 0)); + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar1, + ARM64_SYS_REG(3, 0, 0, 6, 1)); + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64pfr0, + ARM64_SYS_REG(3, 0, 0, 4, 0)); + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64pfr1, + ARM64_SYS_REG(3, 0, 0, 4, 1)); + + /* + * Note that if AArch32 support is not present in the host, + * the AArch32 sysregs are present to be read, but will + * return UNKNOWN values. This is neither better nor worse + * than skipping the reads and leaving 0, as we must avoid + * considering the values in every case. + */ + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar0, + ARM64_SYS_REG(3, 0, 0, 2, 0)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar1, + ARM64_SYS_REG(3, 0, 0, 2, 1)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar2, + ARM64_SYS_REG(3, 0, 0, 2, 2)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar3, + ARM64_SYS_REG(3, 0, 0, 2, 3)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar4, + ARM64_SYS_REG(3, 0, 0, 2, 4)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar5, + ARM64_SYS_REG(3, 0, 0, 2, 5)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar6, + ARM64_SYS_REG(3, 0, 0, 2, 7)); + + err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr0, + ARM64_SYS_REG(3, 0, 0, 3, 0)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr1, + ARM64_SYS_REG(3, 0, 0, 3, 1)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr2, + ARM64_SYS_REG(3, 0, 0, 3, 2)); + kvm_arm_destroy_scratch_host_vcpu(fdarray); + if (err < 0) { + return false; + } + /* We can assume any KVM supporting CPU is at least a v8 * with VFPv4+Neon; this in turn implies most of the other * feature bits. -- 2.17.2