On Wed, 28 Nov 2018 11:19:34 +0100
Michael Mueller <mimu@xxxxxxxxxxxxx> wrote:
> The GIB (Guest Information Block) links the GISA of all guests
> that have adapter interrupts pending. These interrupts cannot be
> delivered because no vcpu of these guests is currently running in
> SIE context. Instead, a GIB alert is issued on the host to schedule
> these guests to run.
>
> This mechanism allows to process adapter interrupts for currently
> not running guests.
>
> The GIB is created during host initialization and associated with
> the Adapter Interruption Facility in case an Adapter Interruption
> Virtualization Facility is available.
>
> Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> arch/s390/include/asm/kvm_host.h | 10 ++++++++++
> arch/s390/kvm/interrupt.c | 37 +++++++++++++++++++++++++++++++++++++
> arch/s390/kvm/kvm-s390.c | 1 +
> arch/s390/kvm/kvm-s390.h | 2 ++
> 4 files changed, 50 insertions(+)
>
> +int kvm_s390_gib_init(u8 nisc)
> +{
> + if (!css_general_characteristics.aiv) {
> + KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
> + return 0;
> + }
> +
> + gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
> + if (!gib) {
> + KVM_EVENT(3, "gib 0x%pK memory allocation failed", gib);
Just noticed this... isn't the dbf torn down again if kvm init failed,
rendering this message inaccessible? Do we need different logging for
fatal errors?
(The code is not wrong, but this logging looks a bit useless.)
> + return -ENOMEM;
> + }
> +
> + gib->nisc = nisc;
> + if (chsc_sgib((u32)(u64)gib)) {
> + KVM_EVENT(3, "gib 0x%pK AIV association failed", gib);
> + free_page((unsigned long)gib);
> + gib = NULL;
> + return -EIO;
> + }
> +
> + KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
> + return 0;
> +}
