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>

1 files changed, 33 insertions, 31 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 3bf0a345224a..f127fb723f2f 100644
--- 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)