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Subject[PATCH 08/13] KVM: Update Posted-Interrupts descriptor during VCPU scheduling
Date
Update Posted-Interrupts descriptor according to the
following rules:
- Before VCPU block, set 'NV' to POSTED_INTR_WAKEUP_VECTOR
- After VCPU block, set 'NV' back to POSTED_INTR_VECTOR

Signed-off-by: Feng Wu <feng.wu@intel.com>
---
arch/x86/include/asm/kvm_host.h | 5 ++
arch/x86/kvm/vmx.c | 83 +++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 16 +++++++
virt/kvm/kvm_main.c | 11 +++++
4 files changed, 115 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0630161..71cfe3e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -773,6 +773,8 @@ struct kvm_x86_ops {

void (*sched_in)(struct kvm_vcpu *kvm, int cpu);
u64 (*get_pi_desc_addr)(struct kvm_vcpu *vcpu);
+ int (*vcpu_pre_block)(struct kvm_vcpu *vcpu);
+ void (*vcpu_post_block)(struct kvm_vcpu *vcpu);
};

struct kvm_arch_async_pf {
@@ -1095,4 +1097,7 @@ int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
void kvm_handle_pmu_event(struct kvm_vcpu *vcpu);
void kvm_deliver_pmi(struct kvm_vcpu *vcpu);

+int kvm_arch_vcpu_pre_block(struct kvm_vcpu *vcpu);
+void kvm_arch_vcpu_post_block(struct kvm_vcpu *vcpu);
+
#endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f41111f..4c1a966 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9153,6 +9153,86 @@ static void vmx_sched_in(struct kvm_vcpu *vcpu, int cpu)
shrink_ple_window(vcpu);
}

+static int vmx_vcpu_pre_block(struct kvm_vcpu *vcpu)
+{
+ struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
+ struct pi_desc old;
+ struct pi_desc new;
+
+ if (!irq_post_enabled)
+ return 0;
+
+ memset(&old, 0, sizeof(old));
+ memset(&new, 0, sizeof(new));
+
+ do {
+ old.control = new.control = pi_desc->control;
+
+ /*
+ * A posted-interrupt happened in the one of the
+ * following two cases:
+ * 1. After the latest pir-to-virr sync operation
+ * in kvm_arch_vcpu_runnable() function
+ * 2. In this do-while() loop, a posted-interrupt
+ * occurs.
+ *
+ * For either of above cases, we should not block
+ * the VCPU.
+ */
+ if (pi_test_on(pi_desc) == 1) {
+ /*
+ * Need to set this flag, then the inject will
+ * be synced from PIR to vIRR before VM-ENTRY.
+ * In fact, for guest IPI case, in function
+ * vmx_deliver_posted_interrupt(), this flags
+ * has already been set, but if the interrupt
+ * is injected by VT-d PI hardware, we need
+ * to set this.
+ */
+ kvm_make_request(KVM_REQ_EVENT, vcpu);
+ return 1;
+ }
+
+ pi_clear_sn(&new);
+
+ /* set 'NV' to 'wakeup vector' */
+ new.nv = POSTED_INTR_WAKEUP_VECTOR;
+ } while (cmpxchg(&pi_desc->control, old.control, new.control)
+ != old.control);
+
+ return 0;
+}
+
+static void vmx_vcpu_post_block(struct kvm_vcpu *vcpu)
+{
+ struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
+ struct pi_desc old;
+ struct pi_desc new;
+ unsigned int dest = 0;
+
+ if (!irq_post_enabled)
+ return;
+
+ pi_set_sn(pi_desc);
+
+ do {
+ old.control = new.control = pi_desc->control;
+
+ dest = cpu_physical_id(vcpu->cpu);
+
+ if (x2apic_mode)
+ new.ndst = dest;
+ else
+ new.ndst = (dest << 8) & 0xFF00;
+
+ /* set 'NV' to 'notification vector' */
+ new.nv = POSTED_INTR_VECTOR;
+ } while (cmpxchg(&pi_desc->control, old.control, new.control)
+ != old.control);
+
+ pi_clear_sn(pi_desc);
+}
+
static struct kvm_x86_ops vmx_x86_ops = {
.cpu_has_kvm_support = cpu_has_kvm_support,
.disabled_by_bios = vmx_disabled_by_bios,
@@ -9262,6 +9342,9 @@ static struct kvm_x86_ops vmx_x86_ops = {
.sched_in = vmx_sched_in,

.get_pi_desc_addr = vmx_get_pi_desc_addr,
+
+ .vcpu_pre_block = vmx_vcpu_pre_block,
+ .vcpu_post_block = vmx_vcpu_post_block,
};

static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0c19d15..d0c8bb2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7746,6 +7746,22 @@ int kvm_update_pi_irte_common(struct kvm *kvm, struct kvm_vcpu *vcpu,
return 0;
}

+int kvm_arch_vcpu_pre_block(struct kvm_vcpu *vcpu)
+{
+ if (kvm_x86_ops->vcpu_pre_block)
+ return kvm_x86_ops->vcpu_pre_block(vcpu);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_arch_vcpu_pre_block);
+
+void kvm_arch_vcpu_post_block(struct kvm_vcpu *vcpu)
+{
+ if (kvm_x86_ops->vcpu_post_block)
+ kvm_x86_ops->vcpu_post_block(vcpu);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_vcpu_post_block);
+
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 25ffac9..1be1a45 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1754,7 +1754,18 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
if (signal_pending(current))
break;

+#ifdef CONFIG_X86
+ if (kvm_arch_vcpu_pre_block(vcpu) == 1) {
+ kvm_make_request(KVM_REQ_UNHALT, vcpu);
+ break;
+ }
+#endif
+
schedule();
+
+#ifdef CONFIG_X86
+ kvm_arch_vcpu_post_block(vcpu);
+#endif
}

finish_wait(&vcpu->wq, &wait);
--
1.7.1


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