On 2014/12/1 19:43, Paolo Bonzini wrote:
On 01/12/2014 10:28, Tiejun Chen wrote:
In most cases calling hwapic_isr_update(), actually we always
check if kvm_apic_vid_enabled() == 1, and also actually,
kvm_apic_vid_enabled()
-> kvm_x86_ops->vm_has_apicv()
-> vmx_vm_has_apicv() or '0' in svm case
So its unnecessary to recall this inside hwapic_isr_update(), here
just remove vmx_vm_has_apicv() out and follow others.
If you want to do this, please NULL out the function pointer instead, as
KVM already does for hwapic_irr_update.
Are you saying something below?
if (enable_apicv)
...
else {
kvm_x86_ops->hwapic_irr_update = NULL;
But there's a little bit difference to NULL out hwapic_isr_update(),
static int vmx_vm_has_apicv(struct kvm *kvm)
{
return enable_apicv && irqchip_in_kernel(kvm);
}
Yes, I can do something like this,
static __init int hadware_setup(void)
{
...
if (enable_apicv) {
...
if (!irqchip_in_kernel(kvm))
kvm_x86_ops->hwapic_isr_update = NULL;
} else {
...
kvm_x86_ops->hwapic_isr_update = NULL;
But this means we have to revise hadware_setup() to get 'kvm' inside,
then rebase other callers to hwapic_isr_update(), is it really good?
Here what I will intend to do is trying to reduce some cost (reduplicate
check) with a little code, so its may not be worth changing much more.
Tiejun
Paolo
Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
arch/x86/kvm/lapic.c | 3 ++-
arch/x86/kvm/vmx.c | 3 ---
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e0e5642..2ddc426 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1739,7 +1739,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
if (kvm_x86_ops->hwapic_irr_update)
kvm_x86_ops->hwapic_irr_update(vcpu,
apic_find_highest_irr(apic));
- kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
+ if (kvm_apic_vid_enabled(vcpu->kvm))
+ kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
kvm_make_request(KVM_REQ_EVENT, vcpu);
kvm_rtc_eoi_tracking_restore_one(vcpu);
}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6a951d8..f0c16a9 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7406,9 +7406,6 @@ static void vmx_hwapic_isr_update(struct kvm *kvm, int isr)
u16 status;
u8 old;
- if (!vmx_vm_has_apicv(kvm))
- return;
-
if (isr == -1)
isr = 0;
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