[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v7 13/17] Update IRTE according to guest interrupt config changes
>>> On 11.09.15 at 10:29, <feng.wu@xxxxxxxxx> wrote: > @@ -198,6 +199,103 @@ void free_hvm_irq_dpci(struct hvm_irq_dpci *dpci) > xfree(dpci); > } > > +/* > + * This routine handles lowest-priority interrupts using vector-hashing > + * mechanism. As an example, modern Intel CPUs use this method to handle > + * lowest-priority interrupts. > + * > + * Here is the details about the vector-hashing mechanism: > + * 1. For lowest-priority interrupts, store all the possible destination > + * vCPUs in an array. > + * 2. Use "gvec % max number of destination vCPUs" to find the right > + * destination vCPU in the array for the lowest-priority interrupt. > + */ > +static struct vcpu *vector_hashing_dest(const struct domain *d, > + uint32_t dest_id, > + bool_t dest_mode, > + uint8_t gvec) > + > +{ > + unsigned long *dest_vcpu_bitmap; > + unsigned int dest_vcpus = 0; > + unsigned int bitmap_array_size = BITS_TO_LONGS(d->max_vcpus); You use the variable just once. Ditch it, or at least make it const. > + struct vcpu *v, *dest = NULL; > + unsigned int i; > + > + dest_vcpu_bitmap = xzalloc_array(unsigned long, bitmap_array_size); > + if ( !dest_vcpu_bitmap ) > + return NULL; > + > + for_each_vcpu ( d, v ) > + { > + if ( !vlapic_match_dest(vcpu_vlapic(v), NULL, APIC_DEST_NOSHORT, > + dest_id, dest_mode) ) > + continue; > + > + __set_bit(v->vcpu_id, dest_vcpu_bitmap); > + dest_vcpus++; > + } > + > + if ( dest_vcpus != 0 ) > + { > + unsigned int mod = gvec % dest_vcpus; > + unsigned int idx = 0; > + > + for ( i = 0; i <= mod; i++ ) > + { > + idx = find_next_bit(dest_vcpu_bitmap, d->max_vcpus, idx) + 1; > + BUG_ON(idx >= d->max_vcpus); > + } > + > + dest = d->vcpu[idx-1]; Blanks around the - please. > +static struct vcpu *pi_find_dest_vcpu(const struct domain *d, uint32_t > dest_id, > + bool_t dest_mode, uint8_t > delivery_mode, > + uint8_t gvec) > +{ > + unsigned int dest_vcpus = 0; > + struct vcpu *v, *dest = NULL; > + > + if ( delivery_mode == dest_LowestPrio ) > + return vector_hashing_dest(d, dest_id, dest_mode, gvec); > + else if ( delivery_mode == dest_Fixed ) Pointless else. And perhaps this should be switch(delivery_mode) anyway. With those cosmetic issues addressed Acked-by: Jan Beulich <jbeulich@xxxxxxxx> _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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