On 7/17/2020 12:01 PM, Jason Wang wrote:

On 2020/7/16 下午7:23, Zhu Lingshan wrote:

quoted

vDPA devices has dedicated backed hardware like
passthrough-ed devices. Then it is possible to setup irq
offloading to vCPU for vDPA devices. Thus this patch tries to
manipulated assigned device counters via irqbypass manager.

This part needs some tweak, e.g why assigned device could be detected 
through this way.

quoted

We will increase/decrease the assigned device counter in kvm/x86.

And you need explain why we don't need similar thing in other arch.

Thanks

OK Thanks!

quoted

Both vDPA and VFIO would go through this code path.

This code path only affect x86 for now.

Signed-off-by: Zhu Lingshan <redacted>
Suggested-by: Jason Wang <jasowang@redhat.com>
---
  arch/x86/kvm/x86.c | 10 ++++++++--
  1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 00c88c2..20c07d3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c

@@ -10624,11 +10624,17 @@ int kvm_arch_irq_bypass_add_producer(struct 

irq_bypass_consumer *cons,
  {
      struct kvm_kernel_irqfd *irqfd =
          container_of(cons, struct kvm_kernel_irqfd, consumer);
+    int ret;
        irqfd->producer = prod;
+    kvm_arch_start_assignment(irqfd->kvm);
+    ret = kvm_x86_ops.update_pi_irte(irqfd->kvm,
+                     prod->irq, irqfd->gsi, 1);
+
+    if (ret)
+        kvm_arch_end_assignment(irqfd->kvm);
  -    return kvm_x86_ops.update_pi_irte(irqfd->kvm,
-                       prod->irq, irqfd->gsi, 1);
+    return ret;
  }
    void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer 
*cons,