[v4 14/16] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted

Feng Wu
2015-06-11T11:04:38Z

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.wu@intel.com>
---
arch/x86/kvm/vmx.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index dd3c63a..9d9b403 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -46,6 +46,7 @@
#include <asm/debugreg.h>
#include <asm/kexec.h>
#include <asm/apic.h>
+#include <asm/irq_remapping.h>

#include "trace.h"

@@ -2001,10 +2002,43 @@ 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;
+
+ 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;
+ }
+
+ /* Allow posting non-urgent interrupts */
+ new.sn = 0;
+
+ /* 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);
+
+ /* Set SN when the vCPU is preempted */
+ if (vcpu->preempted)
+ pi_set_sn(pi_desc);
+ }
+
__vmx_load_host_state(to_vmx(vcpu));
if (!vmm_exclusive) {
__loaded_vmcs_clear(to_vmx(vcpu)->loaded_vmcs);
--
2.1.0