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KVM: x86: Add lowest-priority support for vt-d posted-interrupts

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Use vector-hashing to deliver lowest-priority interrupts for
VT-d posted-interrupts. This patch extends kvm_intr_is_single_vcpu()
to support lowest-priority handling.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Feng Wu 2016-01-25 16:53:34 +08:00 committed by Paolo Bonzini
parent 520040146a
commit 6228a0da80
1 changed files with 50 additions and 8 deletions
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58
arch/x86/kvm/lapic.c
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@ -798,6 +798,20 @@ out:
return ret; return ret;
} }
/*
* This routine tries to handler interrupts in posted mode, here is how
* it deals with different cases:
* - For single-destination interrupts, handle it in posted mode
* - Else if vector hashing is enabled and it is a lowest-priority
* interrupt, handle it in posted mode and use the following mechanism
* to find the destinaiton vCPU.
* 1. For lowest-priority interrupts, store all the possible
* destination vCPUs in an array.
* 2. Use "guest vector % max number of destination vCPUs" to find
* the right destination vCPU in the array for the lowest-priority
* interrupt.
* - Otherwise, use remapped mode to inject the interrupt.
*/
bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq, bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
struct kvm_vcpu **dest_vcpu) struct kvm_vcpu **dest_vcpu)
{ {
@ -839,16 +853,44 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
if (cid >= ARRAY_SIZE(map->logical_map)) if (cid >= ARRAY_SIZE(map->logical_map))
goto out; goto out;
for_each_set_bit(i, &bitmap, 16) { if (kvm_vector_hashing_enabled() &&
dst = map->logical_map[cid][i]; kvm_lowest_prio_delivery(irq)) {
if (++r == 2) int idx;
unsigned int dest_vcpus;
dest_vcpus = hweight16(bitmap);
if (dest_vcpus == 0)
goto out;
idx = kvm_vector_to_index(irq->vector, dest_vcpus,
&bitmap, 16);
/*
* We may find a hardware disabled LAPIC here, if that
* is the case, print out a error message once for each
* guest and return
*/
dst = map->logical_map[cid][idx];
if (!dst && !kvm->arch.disabled_lapic_found) {
kvm->arch.disabled_lapic_found = true;
printk(KERN_INFO
"Disabled LAPIC found during irq injection\n");
goto out;
}
*dest_vcpu = dst->vcpu;
} else {
for_each_set_bit(i, &bitmap, 16) {
dst = map->logical_map[cid][i];
if (++r == 2)
goto out;
}
if (dst && kvm_apic_present(dst->vcpu))
*dest_vcpu = dst->vcpu;
else
goto out; goto out;
} }
if (dst && kvm_apic_present(dst->vcpu))
*dest_vcpu = dst->vcpu;
else
goto out;
} }
ret = true; ret = true;