On 05.11.18 12:28, Pierre Morel wrote:
On 05/11/2018 10:34, Michael Mueller wrote:
On 31.10.18 09:56, Janosch Frank wrote:
On 25.10.18 14:37, Michael Mueller wrote:
The GIB (Guest Information Block) links the GISA of all guests
that have adapter interrupts pending. These interrupts cannot be
deliverd 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>
---
/*
* sie_page2 has to be allocated as DMA because fac_list, crycb and
* gisa need 31bit addresses in the sie control block.
@@ -829,6 +838,7 @@ struct kvm_arch{
/* subset of available cpu features enabled by user space */
DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS);
struct kvm_s390_gisa *gisa;
+ int gib_in_use;
};
That's a kvm wide value, right? But here we save it per VM.
Is that really necessary or am I missing something?
It is guest related as a guest might decide in future
to not use a GISA.
If it is guest/GISA related, shouldn't the name be more appropriate?
like gisa_in_use instead of gib_in_use?
Isn't it redundant with kvm->arch.gisa != 0
No, its meaning is *not* (kvm->arch.gisa != 0)
It is a combination of both: The guest uses a GISA *and* the host
provides a GIB.
Pls. compare with the implementation in kvm_s390_gisa_init()
Think about it as: "the GIB is in use in view of the guest"
