This patch updates the Posted-Interrupts Descriptor when vCPU
is preempted.

sched out:
- Set 'SN' to suppress furture non-urgent interrupts posted for
the vCPU.

sched in:
- Clear 'SN'
- Change NDST if vCPU is scheduled to a different CPU
- Set 'NV' to POSTED_INTR_VECTOR

Signed-off-by: Feng Wu <feng...@intel.com>
---
 arch/x86/kvm/vmx.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ee3b735..bf2e6cd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1916,10 +1916,54 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int 
cpu)
                vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
                vmx->loaded_vmcs->cpu = cpu;
        }
+
+       if (irq_remapping_cap(IRQ_POSTING_CAP)) {
+               struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
+               struct pi_desc old, new;
+               unsigned int dest;
+
+               memset(&old, 0, sizeof(old));
+               memset(&new, 0, sizeof(new));
+
+               do {
+                       old.control = new.control = pi_desc->control;
+                       if (vcpu->cpu != cpu) {
+                               dest = cpu_physical_id(cpu);
+
+                               if (x2apic_enabled())
+                                       new.ndst = dest;
+                               else
+                                       new.ndst = (dest << 8) & 0xFF00;
+                       }
+
+                       pi_clear_sn(&new);
+
+                       /* set 'NV' to 'notification vector' */
+                       new.nv = POSTED_INTR_VECTOR;
+               } while (cmpxchg(&pi_desc->control, old.control,
+                               new.control) != old.control);
+       }
 }
 
 static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
 {
+       if (irq_remapping_cap(IRQ_POSTING_CAP)) {
+               struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
+               struct pi_desc old, new;
+
+               memset(&old, 0, sizeof(old));
+               memset(&new, 0, sizeof(new));
+
+               /* Set SN when the vCPU is preempted */
+               if (vcpu->preempted) {
+                       do {
+                               old.control = new.control = pi_desc->control;
+                               pi_set_sn(&new);
+                       } while (cmpxchg(&pi_desc->control, old.control,
+                                       new.control) != old.control);
+               }
+       }
+
        __vmx_load_host_state(to_vmx(vcpu));
        if (!vmm_exclusive) {
                __loaded_vmcs_clear(to_vmx(vcpu)->loaded_vmcs);
-- 
1.9.1

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