Re: [PATCH v5 05/15] KVM: s390: unify pending_irqs() and pending_irqs_no_gisa()

[Michael Mueller]

On 20.12.18 12:06, Cornelia Huck wrote:
> On Wed, 19 Dec 2018 20:17:46 +0100
> Michael Mueller <mimu@xxxxxxxxxxxxx> wrote:
>
> > Use a single function with parameter irq_flags to differentiate
> > between cases.
> >
> > New irq flag:
> >     IRQ_FLAG_LOCAL: include vcpu local interruptions pending
> >     IRQ_FLAG_FLOATING: include vcpu floating interruptions pending
> >     IRQ_FLAG_GISA: include GISA interruptions pending in IPM
>
> I presume that means that irqs may be in more than one set? Or are gisa
> irqs not considered floating irqs, because they use a different
> mechanism?

Currently, the interruptions managed in GISA are floating only. But
that might change in future. The idea is not to subsume IRQ_FLAG_GISA
in IRQ_FLAG_FLOATING but to be able to address the right set of 
procedures to determine the irq pending set for a given subset of irq
types that have different implementations.

There might be a better name for IRQ_FLAG_FLOATING then?

> > New irq masks:
> >     IRQ_MASK_ALL: include all types
> >     IRQ_MASK_NO_GISA: include all types but GISA
> >
> > Examples:
> >     pending_irqs(vcpu, IRQ_MASK_ALL)
> >     pending_irqs(vcpu, IRQ_MASK_NO_GISA)
> >
> > There will be more irq flags with upcoming patches.
> >
> > Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
> > ---
> >   arch/s390/kvm/interrupt.c | 33 +++++++++++++++++++++------------
> >   1 file changed, 21 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> > index 093b568b6356..4ab20d2eb180 100644
> > --- a/arch/s390/kvm/interrupt.c
> > +++ b/arch/s390/kvm/interrupt.c
> > @@ -31,6 +31,13 @@
> >   #define PFAULT_DONE 0x0680
> >   #define VIRTIO_PARAM 0x0d00
> >   
> > +#define IRQ_FLAG_LOCAL    0x8000 /* include local interruption pending mask */
> > +#define IRQ_FLAG_FLOATING 0x4000 /* include float interruption pending mask */
> > +#define IRQ_FLAG_GISA     0x2000 /* include GISA interruption pending mask */
> > +
> > +#define IRQ_MASK_ALL      (IRQ_FLAG_LOCAL | IRQ_FLAG_FLOATING | IRQ_FLAG_GISA)
> > +#define IRQ_MASK_NO_GISA  (IRQ_MASK_ALL & ~IRQ_FLAG_GISA)
> > +
> >   /* handle external calls via sigp interpretation facility */
> >   static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
> >   {
> > @@ -237,16 +244,18 @@ static inline int kvm_s390_gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gis
> >   	return test_and_clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
> >   }
> >   
> > -static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)
> > +static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu, u16 irq_flags)
>
> Any deeper reason why this is a u16? 16 bits should be enough for
> everyone? :)

I want to use the 8 bits for the IRQ type and the other 8 for additional 
controls, see: "KVM: s390: restore IAM in get_ipm() when IPM is clean"

> >   {
> > -	return vcpu->kvm->arch.float_int.pending_irqs |
> > -		vcpu->arch.local_int.pending_irqs;
> > -}
> > +	unsigned long pending_irqs = 0;
> >   
> > -static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
> > -{
> > -	return pending_irqs_no_gisa(vcpu) |
> > -		kvm_s390_gisa_get_ipm(vcpu->kvm->arch.gisa) << IRQ_PEND_IO_ISC_7;
> > +	if (irq_flags & IRQ_FLAG_LOCAL)
> > +		pending_irqs |= vcpu->arch.local_int.pending_irqs;
> > +	if (irq_flags & IRQ_FLAG_FLOATING)
> > +		pending_irqs |= vcpu->kvm->arch.float_int.pending_irqs;
> > +	if (irq_flags & IRQ_FLAG_GISA)
> > +		pending_irqs |= kvm_s390_gisa_get_ipm(vcpu->kvm->arch.gisa) <<
> > +			IRQ_PEND_IO_ISC_7;
> > +	return pending_irqs;
> >   }
> >   
> >   static inline int isc_to_irq_type(unsigned long isc)
> > @@ -275,7 +284,7 @@ static unsigned long deliverable_irqs(struct kvm_vcpu *vcpu)
> >   {
> >   	unsigned long active_mask;
> >   
> > -	active_mask = pending_irqs(vcpu);
> > +	active_mask = pending_irqs(vcpu, IRQ_MASK_ALL);
> >   	if (!active_mask)
> >   		return 0;
> >   
> > @@ -343,7 +352,7 @@ static void __reset_intercept_indicators(struct kvm_vcpu *vcpu)
> >   
> >   static void set_intercept_indicators_io(struct kvm_vcpu *vcpu)
> >   {
> > -	if (!(pending_irqs_no_gisa(vcpu) & IRQ_PEND_IO_MASK))
> > +	if (!(pending_irqs(vcpu, IRQ_MASK_NO_GISA) & IRQ_PEND_IO_MASK))
>
> I/O interrupts are always floating, so you probably could check for
> only floating (excluding gisa) irqs here.

That's right.

> >   		return;
> >   	else if (psw_ioint_disabled(vcpu))
> >   		kvm_s390_set_cpuflags(vcpu, CPUSTAT_IO_INT);Store Data
> > @@ -353,7 +362,7 @@ static void set_intercept_indicators_io(struct kvm_vcpu *vcpu)
> >