accel/kvm: Add pre-park vCPU support

For that KVM do not support dynamic adjustment of vCPU count,
we must pre-park all possible vCPU at start.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
(cherry picked from commit 000c4a3d545146ee38ea4334fee3a93669c11b28)

accel-kvm-Add-pre-park-vCPU-support.patch

@@ -0,0 +1,64 @@
+From c950cda47386360e37a89dfa7029d83e33888a40 Mon Sep 17 00:00:00 2001
+From: Keqian Zhu <zhukeqian1@huawei.com>
+Date: Fri, 10 Apr 2020 13:04:40 +0800
+Subject: [PATCH] accel/kvm: Add pre-park vCPU support
+
+For that KVM do not support dynamic adjustment of vCPU count,
+we must pre-park all possible vCPU at start.
+
+Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
+Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
+---
+ accel/kvm/kvm-all.c  | 23 +++++++++++++++++++++++
+ include/sysemu/kvm.h |  1 +
+ 2 files changed, 24 insertions(+)
+
+diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
+index 8a98446b7c..f2ce5cd45a 100644
+--- a/accel/kvm/kvm-all.c
++++ b/accel/kvm/kvm-all.c
+@@ -433,6 +433,29 @@ void kvm_destroy_vcpu(CPUState *cpu)
+     }
+ }
+ 
++int kvm_create_parked_vcpu(unsigned long vcpu_id)
++{
++    KVMState *s = kvm_state;
++    struct KVMParkedVcpu *vcpu = NULL;
++    int ret;
++
++    DPRINTF("kvm_create_parked_vcpu\n");
++
++    ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id);
++    if (ret < 0) {
++        DPRINTF("kvm_create_vcpu failed\n");
++        goto err;
++    }
++
++    vcpu = g_malloc0(sizeof(*vcpu));
++    vcpu->vcpu_id = vcpu_id;
++    vcpu->kvm_fd = ret;
++    QLIST_INSERT_HEAD(&s->kvm_parked_vcpus, vcpu, node);
++
++err:
++    return ret;
++}
++
+ static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id)
+ {
+     struct KVMParkedVcpu *cpu;
+diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
+index 7b22aeb6ae..2623775c27 100644
+--- a/include/sysemu/kvm.h
++++ b/include/sysemu/kvm.h
+@@ -221,6 +221,7 @@ int kvm_has_pit_state2(void);
+ int kvm_has_many_ioeventfds(void);
+ int kvm_has_gsi_routing(void);
+ int kvm_has_intx_set_mask(void);
++int kvm_create_parked_vcpu(unsigned long vcpu_id);
+ 
+ /**
+  * kvm_arm_supports_user_irq
+-- 
+2.27.0
+