KVM: ia64: Don't hold slots_lock in guest mode

Reorder locking to avoid holding the slots_lock when entering
the guest.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by : Xiantao Zhang<xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 3bf0a34..f127fb7 100644 (file)
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -632,34 +632,22 @@ static int kvm_vcpu_pre_transition(struct kvm_vcpu *vcpu)
        vti_set_rr6(vcpu->arch.vmm_rr);
        return kvm_insert_vmm_mapping(vcpu);
 }
+
 static void kvm_vcpu_post_transition(struct kvm_vcpu *vcpu)
 {
        kvm_purge_vmm_mapping(vcpu);
        vti_set_rr6(vcpu->arch.host_rr6);
 }
 
-static int  vti_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
        union context *host_ctx, *guest_ctx;
        int r;
 
-       /*Get host and guest context with guest address space.*/
-       host_ctx = kvm_get_host_context(vcpu);
-       guest_ctx = kvm_get_guest_context(vcpu);
-
-       r = kvm_vcpu_pre_transition(vcpu);
-       if (r < 0)
-               goto out;
-       kvm_vmm_info->tramp_entry(host_ctx, guest_ctx);
-       kvm_vcpu_post_transition(vcpu);
-       r = 0;
-out:
-       return r;
-}
-
-static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
-{
-       int r;
+       /*
+        * down_read() may sleep and return with interrupts enabled
+        */
+       down_read(&vcpu->kvm->slots_lock);
 
 again:
        if (signal_pending(current)) {
@@ -668,23 +656,28 @@ again:
                goto out;
        }
 
-       /*
-        * down_read() may sleep and return with interrupts enabled
-        */
-       down_read(&vcpu->kvm->slots_lock);
-
        preempt_disable();
        local_irq_disable();
 
+       /*Get host and guest context with guest address space.*/
+       host_ctx = kvm_get_host_context(vcpu);
+       guest_ctx = kvm_get_guest_context(vcpu);
+
        vcpu->guest_mode = 1;
+
+       r = kvm_vcpu_pre_transition(vcpu);
+       if (r < 0)
+               goto vcpu_run_fail;
+
+       up_read(&vcpu->kvm->slots_lock);
        kvm_guest_enter();
-       r = vti_vcpu_run(vcpu, kvm_run);
-       if (r < 0) {
-               local_irq_enable();
-               preempt_enable();
-               kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
-               goto out;
-       }
+
+       /*
+        * Transition to the guest
+        */
+       kvm_vmm_info->tramp_entry(host_ctx, guest_ctx);
+
+       kvm_vcpu_post_transition(vcpu);
 
        vcpu->arch.launched = 1;
        vcpu->guest_mode = 0;
@@ -698,9 +691,10 @@ again:
         */
        barrier();
        kvm_guest_exit();
-       up_read(&vcpu->kvm->slots_lock);
        preempt_enable();
 
+       down_read(&vcpu->kvm->slots_lock);
+
        r = kvm_handle_exit(kvm_run, vcpu);
 
        if (r > 0) {
@@ -709,12 +703,20 @@ again:
        }
 
 out:
+       up_read(&vcpu->kvm->slots_lock);
        if (r > 0) {
                kvm_resched(vcpu);
+               down_read(&vcpu->kvm->slots_lock);
                goto again;
        }
 
        return r;
+
+vcpu_run_fail:
+       local_irq_enable();
+       preempt_enable();
+       kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+       goto out;
 }
 
 static void kvm_set_mmio_data(struct kvm_vcpu *vcpu)