From: Yi Wang <foxywang@xxxxxxxxxxx>
Add a new function to setup empty irq routing in kvm path, which
can be invoded in non-architecture-specific functions. The difference
compared to the kvm_setup_empty_irq_routing() is this function just
alloc the empty irq routing and does not need synchronize srcu, as
we will call it in kvm_create_vm().
Using the new adding function, we can setup empty irq routing when
kvm_create_vm(), so that x86 and s390 no longer need to set
empty/dummy irq routing when creating an IRQCHIP 'cause it avoid
an synchronize_srcu.
Signed-off-by: Yi Wang <foxywang@xxxxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/irqchip.c | 19 +++++++++++++++++++
virt/kvm/kvm_main.c | 4 ++++
3 files changed, 24 insertions(+)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 48f31dcd318a..9256539139ef 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2100,6 +2100,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
const struct kvm_irq_routing_entry *entries,
unsigned nr,
unsigned flags);
+int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm);
int kvm_set_routing_entry(struct kvm *kvm,
struct kvm_kernel_irq_routing_entry *e,
const struct kvm_irq_routing_entry *ue);
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 1e567d1f6d3d..266bab99a8a8 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -237,3 +237,22 @@ int kvm_set_irq_routing(struct kvm *kvm,
return r;
}
+
+int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm)
+{
+ struct kvm_irq_routing_table *new;
+ int chip_size;
+
+ new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT);
+ if (!new)
+ return -ENOMEM;
+
+ new->nr_rt_entries = 1;
+
+ chip_size = sizeof(int) * KVM_NR_IRQCHIPS * KVM_IRQCHIP_NUM_PINS;
+ memset(new->chip, -1, chip_size);
+
+ RCU_INIT_POINTER(kvm->irq_routing, new);
+
+ return 0;
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ff0a20565f90..b5f4fa9d050d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1285,6 +1285,10 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
if (r)
goto out_err;
+ r = kvm_setup_empty_irq_routing_lockless(kvm);
+ if (r)
+ goto out_err;
+
mutex_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
mutex_unlock(&kvm_lock);
--
2.39.3
