Hi Drew, On 6/21/19 6:34 PM, Andrew Jones wrote: > If -cpu <cpu>,aarch64=off is used then KVM must also be used, and it > and the host must support running the vcpu in 32-bit mode. Also, if > -cpu <cpu>,aarch64=on is used, then it doesn't matter if kvm is > enabled or not. > > Signed-off-by: Andrew Jones <drjo...@redhat.com>
> --- > target/arm/cpu64.c | 12 ++++++------ > target/arm/kvm64.c | 11 +++++++++++ > target/arm/kvm_arm.h | 14 ++++++++++++++ > 3 files changed, 31 insertions(+), 6 deletions(-) > > diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c > index 1901997a0645..946994838d8a 100644 > --- a/target/arm/cpu64.c > +++ b/target/arm/cpu64.c > @@ -407,13 +407,13 @@ static void aarch64_cpu_set_aarch64(Object *obj, bool > value, Error **errp) > * restriction allows us to avoid fixing up functionality that assumes a > * uniform execution state like do_interrupt. > */> - if (!kvm_enabled()) { > - error_setg(errp, "'aarch64' feature cannot be disabled " > - "unless KVM is enabled"); > - return; > - } > - > if (value == false) { > + if (!kvm_enabled() || !kvm_arm_aarch32_supported(CPU(cpu))) { > + error_setg(errp, "'aarch64' feature cannot be disabled " > + "unless KVM is enabled and 32-bit EL1 " > + "is supported"); > + return; > + } > unset_feature(&cpu->env, ARM_FEATURE_AARCH64); > } else { > set_feature(&cpu->env, ARM_FEATURE_AARCH64); > diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c > index 22d19c9aec6f..45ccda589903 100644 > --- a/target/arm/kvm64.c > +++ b/target/arm/kvm64.c > @@ -24,7 +24,9 @@ > #include "exec/gdbstub.h" > #include "sysemu/sysemu.h" > #include "sysemu/kvm.h" > +#include "sysemu/kvm_int.h" > #include "kvm_arm.h" > +#include "hw/boards.h" > #include "internals.h" > > static bool have_guest_debug; > @@ -593,6 +595,15 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures > *ahcf) > return true; > } > > +bool kvm_arm_aarch32_supported(CPUState *cpu) > +{ > + KVMState *s = KVM_STATE(current_machine->accelerator); > + int ret; > + > + ret = kvm_check_extension(s, KVM_CAP_ARM_EL1_32BIT); > + return ret > 0; nit: return kvm_check_extension() should be sufficient > +} > + > #define ARM_CPU_ID_MPIDR 3, 0, 0, 0, 5 > > int kvm_arch_init_vcpu(CPUState *cs) > diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h > index 2a07333c615f..812125f805a1 100644 > --- a/target/arm/kvm_arm.h > +++ b/target/arm/kvm_arm.h > @@ -207,6 +207,15 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures > *ahcf); > */ > void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu); > > +/** > + * kvm_arm_aarch32_supported: > + * @cs: CPUState use kernel-doc comment style? > + * > + * Returns true if the KVM VCPU can enable AArch32 mode and false > + * otherwise. > + */ > +bool kvm_arm_aarch32_supported(CPUState *cs); > + > /** > * kvm_arm_get_max_vm_ipa_size - Returns the number of bits in the > * IPA address space supported by KVM > @@ -247,6 +256,11 @@ static inline void > kvm_arm_set_cpu_features_from_host(ARMCPU *cpu) > cpu->host_cpu_probe_failed = true; > } > > +static inline bool kvm_arm_aarch32_supported(CPUState *cs) > +{ > + return false; > +} > + > static inline int kvm_arm_get_max_vm_ipa_size(MachineState *ms) > { > return -ENOENT; > Reviewed-by: Eric Auger <eric.au...@redhat.com> Thanks Eric