On 09/10/2012 04:09 PM, Gleb Natapov wrote:
> Most interrupt are delivered to only one vcpu. Use pre-build tables to
> find interrupt destination instead of looping through all vcpus.
>
> +
> +static inline int recalculate_apic_map(struct kvm *kvm)
> +{
> + struct kvm_apic_map *new, *old = NULL;
> + struct kvm_vcpu *vcpu;
> + int i;
> +
> + new = kzalloc(sizeof(struct kvm_apic_map), GFP_KERNEL);
> +
> + if (!new)
> + return -ENOMEM;
> +
> + new->ldr_bits = 8;
> + new->flat = true;
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + u16 cid, lid;
> + struct kvm_lapic *apic = vcpu->arch.apic;
> +
> + if (!kvm_apic_present(vcpu))
> + continue;
> +
> + if (apic_x2apic_mode(apic)) {
> + new->ldr_bits = 32;
> + new->flat = false;
> + } else if (kvm_apic_sw_enabled(apic) && new->flat &&
> + kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER)
> + new->flat = false;
> +
> + new->phys_map[kvm_apic_id(apic)] = apic;
> + kvm_apic_get_logical_id(kvm_apic_get_reg(apic, APIC_LDR),
> + new->flat, new->ldr_bits, &cid, &lid);
> +
> + if (lid)
> + new->logical_map[cid][ffs(lid) - 1] = apic;
> + }
> + mutex_lock(&kvm->arch.apic_map_lock);
> + old = kvm->arch.apic_map;
> + rcu_assign_pointer(kvm->arch.apic_map, new);
> + mutex_unlock(&kvm->arch.apic_map_lock);
is this not racy?
cpu 0 cpu 1
---------------- -----------------
new apic id
recalculate
new apic id
recalculate
take lock
install map
drop lock
take lock
install map
drop lock
> +
> + if (old)
> + call_rcu(&old->rcu, rcu_free_apic_map);
> +
> + return 0;
> +}
> +
> -
> static const unsigned int apic_lvt_mask[APIC_LVT_NUM] = {
> LVT_MASK , /* part LVTT mask, timer mode mask added at runtime */
> LVT_MASK | APIC_MODE_MASK, /* LVTTHMR */
> @@ -477,6 +562,67 @@ int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
> return result;
> }
>
> +bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
> + struct kvm_lapic_irq *irq, int *r)
> +{
> + unsigned long bitmap = 1;
> + struct kvm_lapic **dst;
> + int i;
> +
> + if (irq->shorthand == APIC_DEST_SELF) {
> + *r = kvm_apic_set_irq(src->vcpu, irq);
> + return true;
> + }
> +
> + if (irq->shorthand)
> + return false;
> +
> + if (irq->dest_mode == 0) { /* physical mode */
> + if (irq->delivery_mode == APIC_DM_LOWEST ||
> + irq->dest_id == 0xff)
> + return false;
> + rcu_read_lock();
Unmatched rcu_read_lock() inside a block is ugly, please start it earlier.
> + dst = &kvm->arch.apic_map->phys_map[irq->dest_id & 0xff];
Like mst says, rcu_dereference().
> + } else {
> + u16 cid, lid;
> + u32 mda = irq->dest_id;
> +
> + rcu_read_lock();
> + if (kvm->arch.apic_map->ldr_bits == 8)
> + mda <<= 24;
> +
> + kvm_apic_get_logical_id(mda, kvm->arch.apic_map->flat,
> + kvm->arch.apic_map->ldr_bits, &cid, &lid);
> + dst = kvm->arch.apic_map->logical_map[cid];
> +
> + bitmap = lid;
> + if (irq->delivery_mode == APIC_DM_LOWEST) {
> + int l = -1;
> + for_each_set_bit(i, &bitmap, 16) {
> + if (!dst[i])
> + continue;
> + if (l < 0)
> + l = i;
> + else if (kvm_apic_compare_prio(dst[i]->vcpu, dst[l]->vcpu) < 0)
> + l = i;
> + }
> +
> + bitmap = (l >= 0) ? 1 << l : 0;
> + }
> + }
> +
> + for_each_set_bit(i, &bitmap, 16) {
> + if (!dst[i])
> + continue;
> + if (*r < 0)
> + *r = 0;
> + *r += kvm_apic_set_irq(dst[i]->vcpu, irq);
> + }
> +
> + rcu_read_unlock();
> + return true;
> +}
> +
> /*
> * Add a pending IRQ into lapic.
> * Return 1 if successfully added and 0 if discarded.
> @@ -880,7 +1026,7 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
> switch (reg) {
> case APIC_ID: /* Local APIC ID */
> if (!apic_x2apic_mode(apic))
> - apic_set_reg(apic, APIC_ID, val);
> + kvm_apic_set_id(apic, val >> 24);
> else
> ret = 1;
> break;
> @@ -896,15 +1042,16 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
>
> case APIC_LDR:
> if (!apic_x2apic_mode(apic))
> - apic_set_reg(apic, APIC_LDR, val & APIC_LDR_MASK);
> + kvm_apic_set_ldr(apic, val & APIC_LDR_MASK);
> else
> ret = 1;
> break;
>
> case APIC_DFR:
> - if (!apic_x2apic_mode(apic))
> + if (!apic_x2apic_mode(apic)) {
> apic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
> - else
> + recalculate_apic_map(apic->vcpu->kvm);
> + } else
> ret = 1;
What if these have different settings on different vcpus?
> break;
>
--
error compiling committee.c: too many arguments to function
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