On 09/07/13 15:56, Dominik Dingel wrote:
> This patch enables async page faults for s390 kvm guests.
> It provides the userspace API to enable, disable or get the status of this
> feature. Also it includes the diagnose code, called by the guest to enable
> async page faults.
>
> The async page faults will use an already existing guest interface for this
> purpose, as described in "CP Programming Services (SC24-6084)".
>
> Signed-off-by: Dominik Dingel <din...@linux.vnet.ibm.com>
Re-reading this patch again, found some thing that you should take
care of (nothing major, just small details). Sorry for not seeing them
earlier.
[...]
> + case 1: /* CANCEL */
> + if (vcpu->run->s.regs.gprs[rx] & 7)
> + return kvm_s390_inject_program_int(vcpu,
> PGM_ADDRESSING);
> +
> + vcpu->run->s.regs.gprs[ry] = 0;
> +
> + if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
> + vcpu->run->s.regs.gprs[ry] = 1;
> +
> + vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
> + rc = 0;
> + break;
Dont we need a kvm_clear_async_pf_completion_queue(vcpu) or similar here as
well?
The cancel function is supposed to purge all outstanding requests (those were
no
completion signal was made pending yet)
[...]
> @@ -264,6 +292,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
> {
> VCPU_EVENT(vcpu, 3, "%s", "free cpu");
> trace_kvm_s390_destroy_vcpu(vcpu->vcpu_id);
> + kvm_clear_async_pf_completion_queue(vcpu);
> if (!kvm_is_ucontrol(vcpu->kvm)) {
> clear_bit(63 - vcpu->vcpu_id,
> (unsigned long *) &vcpu->kvm->arch.sca->mcn);
> @@ -313,6 +342,9 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
> /* Section: vcpu related */
> int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> {
> + vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
> + kvm_clear_async_pf_completion_queue(vcpu);
> + kvm_async_pf_wakeup_all(vcpu);
> if (kvm_is_ucontrol(vcpu->kvm)) {
> vcpu->arch.gmap = gmap_alloc(current->mm);
> if (!vcpu->arch.gmap)
We should also reset pfault handling for CPU reset, no?
> @@ -691,10 +723,75 @@ static void kvm_arch_fault_in_sync(struct kvm_vcpu
> *vcpu)
> up_read(&mm->mmap_sem);
> }
>
> +static void __kvm_inject_pfault_token(struct kvm_vcpu *vcpu, bool
> start_token,
> + unsigned long token)
> +{
> + struct kvm_s390_interrupt inti;
> + inti.type = start_token ? KVM_S390_INT_PFAULT_INIT :
> + KVM_S390_INT_PFAULT_DONE;
> + inti.parm64 = token;
> + if (kvm_s390_inject_vcpu(vcpu, &inti))
> + WARN(1, "pfault interrupt injection failed");
> +}
The PFAULT_DONE is architectured as a floating interrupt (can happen
on other CPUs).
[...]
> --- a/arch/s390/kvm/sigp.c
> +++ b/arch/s390/kvm/sigp.c
> @@ -187,6 +187,8 @@ static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32
> parameter)
> {
> int rc;
>
> + vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
> +
sigp set architecture affects all cpus, so we must reset pfault via
kvm_for_each_vcpu, I guess.
Otherwise patch looks good. I guess only one more iteration
Christian
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