Hi Dongjiu Geng, On 09/06/18 13:40, Marc Zyngier wrote: > On Fri, 08 Jun 2018 20:48:40 +0100, Dongjiu Geng wrote: >> For the migrating VMs, user space may need to know the exception >> state. For example, in the machine A, KVM make an SError pending, >> when migrate to B, KVM also needs to pend an SError. >> >> This new IOCTL exports user-invisible states related to SError. >> Together with appropriate user space changes, user space can get/set >> the SError exception state to do migrate/snapshot/suspend. >> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h >> index 04b3256..df4faee 100644 >> --- a/arch/arm64/include/uapi/asm/kvm.h >> +++ b/arch/arm64/include/uapi/asm/kvm.h >> @@ -153,6 +154,18 @@ struct kvm_sync_regs { >> struct kvm_arch_memory_slot { >> }; >> >> +/* for KVM_GET/SET_VCPU_EVENTS */ >> +struct kvm_vcpu_events { >> + struct { >> + __u8 serror_pending; >> + __u8 serror_has_esr; >> + /* Align it to 8 bytes */ >> + __u8 pad[6]; >> + __u64 serror_esr; >> + } exception; >> + __u32 reserved[12]; >> +}; >> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c >> index 56a0260..4426915 100644 >> --- a/arch/arm64/kvm/guest.c >> +++ b/arch/arm64/kvm/guest.c >> +int kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu, >> + struct kvm_vcpu_events *events) >> +{ >> + bool serror_pending = events->exception.serror_pending; >> + bool has_esr = events->exception.serror_has_esr; >> + >> + if (serror_pending && has_esr) { >> + if (!cpus_have_const_cap(ARM64_HAS_RAS_EXTN)) >> + return -EINVAL; >> + >> + kvm_set_sei_esr(vcpu, events->exception.serror_esr); >> + } else if (serror_pending) { >> + kvm_inject_vabt(vcpu); >> + } >> + >> + return 0; > > There was an earlier request to check that all the padding is set to > zero. I still think this makes sense. I agree, not just the exception.padding[], but reserved[] too. Thanks, James -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html