On 05.12.19 13:09, Janosch Frank wrote:
[...]
> +4.123 KVM_S390_CLEAR_RESET
> +
> +Capability: KVM_CAP_S390_VCPU_RESETS
> +Architectures: s390
> +Type: vcpu ioctl
> +Parameters: none
> +Returns: 0
> +
> +This ioctl resets VCPU registers and control structures that QEMU
> +can't access via the kvm_run structure. The clear reset is a superset
> +of the initial reset and additionally clears general, access, floating
> +and vector registers.
As Thomas outlined, make it more obvious that userspace does the remaining
parts. I do not think that we want the kernel to do the things (unless it
helps you in some way for the ultravisor guests)
[...]
>
> +static int kvm_arch_vcpu_ioctl_normal_reset(struct kvm_vcpu *vcpu)
> +{
> + kvm_clear_async_pf_completion_queue(vcpu);
> + kvm_s390_clear_local_irqs(vcpu);
> + return 0;
Shouldnt we also do
if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
kvm_s390_vcpu_stop(vcpu);
here?
> +}
> +
> static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
> {
> kvm_s390_vcpu_initial_reset(vcpu);
> @@ -4363,9 +4371,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
> r = kvm_arch_vcpu_ioctl_set_initial_psw(vcpu, psw);
> break;
> }
> +
> + case KVM_S390_CLEAR_RESET:
> + /* fallthrough */
> case KVM_S390_INITIAL_RESET:
> r = kvm_arch_vcpu_ioctl_initial_reset(vcpu);
> break;
Then we could also do a fallthrough here and do:
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index d9e6bf3..c715ae3 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2867,10 +2867,6 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->pp = 0;
vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
- kvm_clear_async_pf_completion_queue(vcpu);
- if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
- kvm_s390_vcpu_stop(vcpu);
- kvm_s390_clear_local_irqs(vcpu);
}
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
> + case KVM_S390_NORMAL_RESET:
> + r = kvm_arch_vcpu_ioctl_normal_reset(vcpu);
> + break;
> case KVM_SET_ONE_REG:
> case KVM_GET_ONE_REG: {
