1 files changed, 28 insertions, 0 deletions
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index 34d5bc1bc9..4883b95d9d 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -52,6 +52,34 @@ int kvm_xen_init(KVMState *s, uint32_t hypercall_msr)
     return 0;
 }
 
+int kvm_xen_init_vcpu(CPUState *cs)
+{
+    int err;
+
+    /*
+     * The kernel needs to know the Xen/ACPI vCPU ID because that's
+     * what the guest uses in hypercalls such as timers. It doesn't
+     * match the APIC ID which is generally used for talking to the
+     * kernel about vCPUs. And if vCPU threads race with creating
+     * their KVM vCPUs out of order, it doesn't necessarily match
+     * with the kernel's internal vCPU indices either.
+     */
+    if (kvm_xen_has_cap(EVTCHN_SEND)) {
+        struct kvm_xen_vcpu_attr va = {
+            .type = KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID,
+            .u.vcpu_id = cs->cpu_index,
+        };
+        err = kvm_vcpu_ioctl(cs, KVM_XEN_VCPU_SET_ATTR, &va);
+        if (err) {
+            error_report("kvm: Failed to set Xen vCPU ID attribute: %s",
+                         strerror(-err));
+            return err;
+        }
+    }
+
+    return 0;
+}
+
 uint32_t kvm_xen_get_caps(void)
 {
     return kvm_state->xen_caps;