2016-03-18 02:44+0700, Suravee Suthikulpanit:
> On 3/10/16 03:55, Radim Krčmář wrote:
>>2016-03-04 14:46-0600, Suravee Suthikulpanit:
>>>>From: Suravee Suthikulpanit<suravee.suthikulpanit@xxxxxxx>
>>>>
>>>>Introduce VMEXIT handlers, avic_incp_ipi_interception() and
>>>>avic_noaccel_interception().
>>>>
>>>>Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpanit@xxxxxxx>
>>>>---
>>>>diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>>>>@@ -3690,6 +3690,264 @@ static int mwait_interception(struct vcpu_svm *svm)
>>>>+ case AVIC_INCMP_IPI_ERR_TARGET_NOT_RUN: {
>>>>+ kvm_for_each_vcpu(i, vcpu, kvm) {
>>>>+ if (!kvm_apic_match_dest(vcpu, apic,
>>>>+ icrl & APIC_SHORT_MASK,
>>>>+ GET_APIC_DEST_FIELD(icrh),
>>>>+ icrl & APIC_DEST_MASK))
>>>>+ continue;
>>>>+
>>>>+ kvm_vcpu_kick(vcpu);
>>KVM shouldn't kick VCPUs that are running. (Imagine a broadcast when
>>most VCPUs are in guest mode.)
>
> So, besides checking if the vcpu match the destination, I will add the check
> to see if the is_running bit is set before calling kvm_vcpu_kick()
That will do.
>>I think a new helper might be useful here: we only want to wake up from
>>wait queue, but never force VCPU out of guest mode ... kvm_vcpu_kick()
>>does both.
>
> If I only kick non-running vcpu, do I still need this new helper function?
I would prefer it. It's a minor performance optimization (non-running
VCPUs aren't in guest mode) and makes our intent clear. Please use
include the following patch and use kvm_vcpu_wake_up instead.
---8<---
AVIC has a use for kvm_vcpu_wake_up.
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 19 +++++++++++++------
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 861f690aa791..7b269626a3b3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -650,6 +650,7 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
void kvm_vcpu_block(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu);
+void kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);
void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
int kvm_vcpu_yield_to(struct kvm_vcpu *target);
void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1eae05236347..c39c54afdb74 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2054,13 +2054,8 @@ out:
EXPORT_SYMBOL_GPL(kvm_vcpu_block);
#ifndef CONFIG_S390
-/*
- * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
- */
-void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+void kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
{
- int me;
- int cpu = vcpu->cpu;
wait_queue_head_t *wqp;
wqp = kvm_arch_vcpu_wq(vcpu);
@@ -2068,6 +2063,18 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
wake_up_interruptible(wqp);
++vcpu->stat.halt_wakeup;
}
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
+
+/*
+ * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
+ */
+void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+{
+ int me;
+ int cpu = vcpu->cpu;
+
+ kvm_vcpu_wake_up(vcpu);
me = get_cpu();
if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
--
2.7.2
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