Hi Marc,
On 2014/11/14 20:11, Marc Zyngier wrote:
> Shannon,
>
> On 14/11/14 11:09, Shannon Zhao wrote:
>> When call kvm_vgic_inject_irq to inject irq, we've already known
>> which vcpu the IRQ for form the cpuid. So we should just kick this
>> one vcpu to avoid iterate through all.
>
> Have you actually tested this? Hint: cpuid is *not* what you think, and
> I strongly suggest you play with interrupt affinity in the guest before
> posting such changes.
>
So sorry that I didn't consider all cases.
There are three places calling the function "kvm_vgic_inject_irq" :
1) kvm_timer_inject_irq
The "cpuid" is the real cpuid.
kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
timer->irq->irq,
timer->irq->level);
2) kvm_vm_ioctl_irq_line as irq_type is KVM_ARM_IRQ_TYPE_PPI
The "cpuid" is also the real cpuid.
kvm_vgic_inject_irq(kvm, vcpu->vcpu_id, irq_num, level);
3) kvm_vm_ioctl_irq_line as irq_type is KVM_ARM_IRQ_TYPE_SPI
This case is that I missed I think.
The "cpuid" is always zero and should get the cpuid through dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS].
kvm_vgic_inject_irq(kvm, 0, irq_num, level);
So before kicking the vcpu we can get the cpuid through dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS],
then kick the specific vcpu, right?
If right, I make another patch and test on Fastmodel and ARM64 hardware platform as you suggested.
When call kvm_vgic_inject_irq to inject irq, we can known which vcpu
the IRQ for through the irq_num and the cpuid. So we should just kick
this vcpu to avoid iterating through all.
Signed-off-by: Shannon Zhao <zhaoshenglong@xxxxxxxxxx>
---
virt/kvm/arm/vgic.c | 22 +++++++++++++++++++++-
1 files changed, 21 insertions(+), 1 deletions(-)
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 82db9d6..860c3ff 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -95,6 +95,7 @@ static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu);
static void vgic_update_state(struct kvm *kvm);
static void vgic_kick_vcpus(struct kvm *kvm);
+static void vgic_kick_vcpu(struct kvm *kvm, int cpuid, unsigned int irq_num);
static u8 *vgic_get_sgi_sources(struct vgic_dist *dist, int vcpu_id, int sgi);
static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
@@ -1589,6 +1590,25 @@ static void vgic_kick_vcpus(struct kvm *kvm)
}
}
+static void vgic_kick_vcpu(struct kvm *kvm, int cpuid, unsigned int irq_num)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct kvm_vcpu *vcpu;
+
+ /*
+ * We've injected an interrupt, kick the specified vcpu
+ */
+ if (irq_num >= VGIC_NR_PRIVATE_IRQS)
+ cpuid = dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS];
+
+ if (cpuid < atomic_read(&kvm->online_vcpus)) {
+ vcpu = kvm_get_vcpu(kvm, cpuid);
+ if (vcpu != NULL) {
+ kvm_vcpu_kick(vcpu);
+ }
+ }
+}
+
static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level)
{
int edge_triggered = vgic_irq_is_edge(vcpu, irq);
@@ -1694,7 +1714,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
{
if (likely(vgic_initialized(kvm)) &&
vgic_update_irq_pending(kvm, cpuid, irq_num, level))
- vgic_kick_vcpus(kvm);
+ vgic_kick_vcpu(kvm, cpuid, irq_num);
return 0;
}
--
1.7.1
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