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@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 234f720..9c87064 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -45,6 +45,7 @@
#include <asm/debugreg.h>
#include <asm/kexec.h>
#include <asm/apic.h>
+#include <asm/irq_remapping.h>
#include "trace.h"
#include "pmu.h"
@@ -2001,10 +2002,60 @@ 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 'nv' field is POSTED_INTR_WAKEUP_VECTOR, there
+ * are two possible cases:
+ * 1. After running 'pi_pre_block', context switch
+ * happened. For this case, 'sn' was set in
+ * vmx_vcpu_put(), so we need to clear it here.
+ * 2. After running 'pi_pre_block', we were blocked,
+ * and woken up by some other guy. For this case,
+ * we don't need to do anything, 'pi_post_block'
+ * will do everything for us. However, we cannot
+ * check whether it is case #1 or case #2 here
+ * (maybe, not needed), so we also clear sn here,
+ * I think it is not a big deal.
+ */
+ if (pi_desc->nv != POSTED_INTR_WAKEUP_VECTOR) {
+ if (vcpu->cpu != cpu) {
+ dest = cpu_physical_id(cpu);
+
+ if (x2apic_enabled())
+ new.ndst = dest;
+ else
+ new.ndst = (dest << 8) & 0xFF00;
+ }
+
+ /* set 'NV' to 'notification vector' */
+ new.nv = POSTED_INTR_VECTOR;
+ }
+
+ /* Allow posting non-urgent interrupts */
+ new.sn = 0;
+ } 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
--
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