On Fri, 10 Jan 2020 05:19:06 -0500
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
> The architecture states that we need to reset local IRQs for all CPU
> resets. Because the old reset interface did not support the normal CPU
> reset we never did that on a normal reset.
>
> Let's implement an interface for the missing normal and clear resets
> and reset all local IRQs, registers and control structures as stated
> in the architecture.
>
> Userspace might already reset the registers via the vcpu run struct,
> but as we need the interface for the interrupt clearing part anyway,
> we implement the resets fully and don't rely on userspace to reset the
> rest.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
>
> Based on the irc discussion.
>
> ---
> Documentation/virt/kvm/api.txt | 43 ++++++++++++
> arch/s390/kvm/kvm-s390.c | 115 +++++++++++++++++++++++----------
> include/uapi/linux/kvm.h | 5 ++
> 3 files changed, 130 insertions(+), 33 deletions(-)
>
(...)
> +static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_sync_regs *regs = &vcpu->run->s.regs;
> +
> + /* Clear reset is a superset of the initial reset */
> + kvm_arch_vcpu_ioctl_normal_reset(vcpu);
> +
> + memset(®s->gprs, 0, sizeof(regs->gprs));
> + /*
> + * Will be picked up via save_fpu_regs() in the initial reset
> + * fallthrough.
Didn't you want to remove that? (Especially now that we don't
fallthrough anymore.)
> + */
> + memset(®s->vrs, 0, sizeof(regs->vrs));
> + memset(®s->acrs, 0, sizeof(regs->acrs));
> +
> + regs->etoken = 0;
> + regs->etoken_extension = 0;
> +
> + memset(®s->gscb, 0, sizeof(regs->gscb));
> + if (MACHINE_HAS_GS) {
> + preempt_disable();
> + __ctl_set_bit(2, 4);
> + if (current->thread.gs_cb) {
> + vcpu->arch.host_gscb = current->thread.gs_cb;
> + save_gs_cb(vcpu->arch.host_gscb);
> + }
> + if (vcpu->arch.gs_enabled) {
> + current->thread.gs_cb = (struct gs_cb *)
> + &vcpu->run->s.regs.gscb;
> + restore_gs_cb(current->thread.gs_cb);
> + }
> + preempt_enable();
> + }
> }
>
> int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> @@ -4363,8 +4403,17 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
> r = kvm_arch_vcpu_ioctl_set_initial_psw(vcpu, psw);
> break;
> }
> + case KVM_S390_CLEAR_RESET:
> + r = 0;
> + kvm_arch_vcpu_ioctl_clear_reset(vcpu);
I'd probably have switched those two lines, but that's a really a
bikeshed thing :)
> + break;
> case KVM_S390_INITIAL_RESET:
> - r = kvm_arch_vcpu_ioctl_initial_reset(vcpu);
> + r = 0;
> + kvm_arch_vcpu_ioctl_initial_reset(vcpu);
> + break;
> + case KVM_S390_NORMAL_RESET:
> + r = 0;
> + kvm_arch_vcpu_ioctl_normal_reset(vcpu);
> break;
> case KVM_SET_ONE_REG:
> case KVM_GET_ONE_REG: {
With the comment removed,
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
