KVM: Break dependency between vcpu index in vcpus array and vcpu_id.
Archs are free to use vcpu_id as they see fit. For x86 it is used as
vcpu's apic id. New ioctl is added to configure boot vcpu id that was
assumed to be 0 till now.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0d54ede..25e1f9c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -689,11 +689,6 @@
}
#endif
-static inline int valid_vcpu(int n)
-{
- return likely(n >= 0 && n < KVM_MAX_VCPUS);
-}
-
inline int kvm_is_mmio_pfn(pfn_t pfn)
{
if (pfn_valid(pfn)) {
@@ -1714,24 +1709,18 @@
*/
static int create_vcpu_fd(struct kvm_vcpu *vcpu)
{
- int fd = anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
- if (fd < 0)
- kvm_put_kvm(vcpu->kvm);
- return fd;
+ return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
}
/*
* Creates some virtual cpus. Good luck creating more than one.
*/
-static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
+static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
{
int r;
struct kvm_vcpu *vcpu;
- if (!valid_vcpu(n))
- return -EINVAL;
-
- vcpu = kvm_arch_vcpu_create(kvm, n);
+ vcpu = kvm_arch_vcpu_create(kvm, id);
if (IS_ERR(vcpu))
return PTR_ERR(vcpu);
@@ -1742,25 +1731,38 @@
return r;
mutex_lock(&kvm->lock);
- if (kvm->vcpus[n]) {
- r = -EEXIST;
+ if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
+ r = -EINVAL;
goto vcpu_destroy;
}
- kvm->vcpus[n] = vcpu;
- if (n == 0)
- kvm->bsp_vcpu = vcpu;
- mutex_unlock(&kvm->lock);
+
+ for (r = 0; r < atomic_read(&kvm->online_vcpus); r++)
+ if (kvm->vcpus[r]->vcpu_id == id) {
+ r = -EEXIST;
+ goto vcpu_destroy;
+ }
+
+ BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
/* Now it's all set up, let userspace reach it */
kvm_get_kvm(kvm);
r = create_vcpu_fd(vcpu);
- if (r < 0)
- goto unlink;
+ if (r < 0) {
+ kvm_put_kvm(kvm);
+ goto vcpu_destroy;
+ }
+
+ kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
+ smp_wmb();
+ atomic_inc(&kvm->online_vcpus);
+
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+ if (kvm->bsp_vcpu_id == id)
+ kvm->bsp_vcpu = vcpu;
+#endif
+ mutex_unlock(&kvm->lock);
return r;
-unlink:
- mutex_lock(&kvm->lock);
- kvm->vcpus[n] = NULL;
vcpu_destroy:
mutex_unlock(&kvm->lock);
kvm_arch_vcpu_destroy(vcpu);
@@ -2233,6 +2235,15 @@
r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
break;
}
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+ case KVM_SET_BOOT_CPU_ID:
+ r = 0;
+ if (atomic_read(&kvm->online_vcpus) != 0)
+ r = -EBUSY;
+ else
+ kvm->bsp_vcpu_id = arg;
+ break;
+#endif
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
}
@@ -2299,6 +2310,9 @@
case KVM_CAP_USER_MEMORY:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+ case KVM_CAP_SET_BOOT_CPU_ID:
+#endif
return 1;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
case KVM_CAP_IRQ_ROUTING: