On 2014/11/18 18:21, Marc Zyngier wrote:
> On 18/11/14 10:12, Shannon Zhao wrote:
>> When call kvm_vgic_inject_irq to inject irq, we can known which vcpu
>> the IRQ for by 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 | 32 ++++++++++++++++++++++++--------
>> 1 files changed, 24 insertions(+), 8 deletions(-)
>>
>> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
>> index 82db9d6..9dad67a 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);
>> 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 +1590,21 @@ static void vgic_kick_vcpus(struct kvm *kvm)
>> }
>> }
>>
>> +static void vgic_kick_vcpu(struct kvm *kvm, int cpuid)
>> +{
>> + struct kvm_vcpu *vcpu;
>> +
>> + /*
>> + * We've injected an interrupt, kick the specified vcpu
>> + */
>> + if (cpuid < atomic_read(&kvm->online_vcpus)) {
>> + vcpu = kvm_get_vcpu(kvm, cpuid);
>> + if (vcpu != NULL) {
>> + kvm_vcpu_kick(vcpu);
>> + }
>> + }
>
> Why do you need all these checks? Why would cpuid be wrong at any time
> here, given that we've extracted it from supposedly valid information?
> Can you give an example of such a situation?
>
Sorry, thanks for your indication.
I considered the situation that guest offline one vcpu which a SPI bind to.
I didn't think clearly before and I have tested at this situation.
It's an overprotection.
So remove the "vgic_kick_vcpu" and just call "kvm_vcpu_kick" in "kvm_vgic_inject_irq" ?
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
bool level)
{
if (likely(vgic_initialized(kvm)) &&
vgic_update_irq_pending(kvm, &cpuid, irq_num, level))
/*
* We've injected an interrupt, kick the specified vcpu
*/
kvm_vcpu_kick(kvm_get_vcpu(kvm, cpuid));
return 0;
}
Thanks,
Shannon
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