kvm: Rework VCPU synchronization

During startup and after reset we have to synchronize user space to the in-kernel KVM state. Namely, we need to transfer the VCPU registers when they change due to VCPU as well as APIC reset. This patch refactors the required hooks so that kvm_init_vcpu registers its own per-VCPU reset handler and adds a cpu_synchronize_state to the APIC reset. That way we no longer depend on the new reset order (and can drop this disliked interface again) and we can even drop a KVM hook in main(). Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

kvm: Rework VCPU synchronization
During startup and after reset we have to synchronize user space to the in-kernel KVM state. Namely, we need to transfer the VCPU registers when they change due to VCPU as well as APIC reset. This patch refactors the required hooks so that kvm_init_vcpu registers its own per-VCPU reset handler and adds a cpu_synchronize_state to the APIC reset. That way we no longer depend on the new reset order (and can drop this disliked interface again) and we can even drop a KVM hook in main(). Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Jan Kiszka · Anthony Liguori
1 parent e9283f8b
Showing 4 changed files with 16 additions and 35 deletions
hw/apic.c
kvm-all.c
kvm.h
vl.c
@@ -23,6 +23,7 @@
 #include "msix.h"
 #include "qemu-timer.h"
 #include "host-utils.h"
+#include "kvm.h"
 //#define DEBUG_APIC
@@ -953,6 +954,8 @@ static void apic_reset(void *opaque)
          */
         s->lvt[APIC_LVT_LINT0] = 0x700;
     }
+
+    cpu_synchronize_state(s->cpu_env, 1);
 }
 static CPUReadMemoryFunc *apic_mem_read[3] = {
@@ -143,6 +143,15 @@ static int kvm_set_user_memory_region(KVMState *s, KVMSlot *slot)
     return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
 }
+static void kvm_reset_vcpu(void *opaque)
+{
+    CPUState *env = opaque;
+
+    if (kvm_arch_put_registers(env)) {
+        fprintf(stderr, "Fatal: kvm vcpu reset failed\n");
+        abort();
+    }
+}
 int kvm_init_vcpu(CPUState *env)
 {
@@ -176,7 +185,10 @@ int kvm_init_vcpu(CPUState *env)
     }
     ret = kvm_arch_init_vcpu(env);
-
+    if (ret == 0) {
+        qemu_register_reset(kvm_reset_vcpu, 0, env);
+        ret = kvm_arch_put_registers(env);
+    }
 err:
     return ret;
 }
@@ -201,21 +213,6 @@ int kvm_get_mp_state(CPUState *env)
     return 0;
 }
-int kvm_sync_vcpus(void)
-{
-    CPUState *env;
-
-    for (env = first_cpu; env != NULL; env = env->next_cpu) {
-        int ret;
-
-        ret = kvm_arch_put_registers(env);
-        if (ret)
-            return ret;
-    }
-
-    return 0;
-}
-
 /*
  * dirty pages logging control
  */
@@ -397,11 +394,6 @@ int kvm_check_extension(KVMState *s, unsigned int extension)
     return ret;
 }
-static void kvm_reset_vcpus(void *opaque)
-{
-    kvm_sync_vcpus();
-}
-
 int kvm_init(int smp_cpus)
 {
     static const char upgrade_note[] =
@@ -492,8 +484,6 @@ int kvm_init(int smp_cpus)
     if (ret < 0)
         goto err;
-    qemu_register_reset(kvm_reset_vcpus, INT_MAX, NULL);
-
     kvm_state = s;
     return 0;
@@ -32,7 +32,6 @@ struct kvm_run;
 int kvm_init(int smp_cpus);
 int kvm_init_vcpu(CPUState *env);
-int kvm_sync_vcpus(void);
 int kvm_cpu_exec(CPUState *env);
@@ -6057,17 +6057,6 @@ int main(int argc, char **argv, char **envp)
     current_machine = machine;
-    /* Set KVM's vcpu state to qemu's initial CPUState. */
-    if (kvm_enabled()) {
-        int ret;
-
-        ret = kvm_sync_vcpus();
-        if (ret < 0) {
-            fprintf(stderr, "failed to initialize vcpus\n");
-            exit(1);
-        }
-    }
-
     /* init USB devices */
     if (usb_enabled) {
         for(i = 0; i < usb_devices_index; i++) {