KVM: PPC: Book3s: PR: Disable preemption in vcpu_run

When entering the guest, we want to make sure we're not getting preempted
away, so let's disable preemption on entry, but enable it again while handling
guest exits.

Reported-by: Jörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 203a7b7b58b9..19af2bf2b87d 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -517,6 +517,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
         run->ready_for_interrupt_injection = 1;
 
         trace_kvm_book3s_exit(exit_nr, vcpu);
+        preempt_enable();
         kvm_resched(vcpu);
         switch (exit_nr) {
         case BOOK3S_INTERRUPT_INST_STORAGE:
@@ -761,6 +762,8 @@ program_interrupt:
                         run->exit_reason = KVM_EXIT_INTR;
                         r = -EINTR;
                 } else {
+                        preempt_disable();
+
                         /* In case an interrupt came in that was triggered
                          * from userspace (like DEC), we need to check what
                          * to inject now! */
@@ -923,10 +926,13 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 #endif
         ulong ext_msr;
 
+        preempt_disable();
+
         /* Check if we can run the vcpu at all */
         if (!vcpu->arch.sane) {
                 kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-                return -EINVAL;
+                ret = -EINVAL;
+                goto out;
         }
 
         kvmppc_core_prepare_to_enter(vcpu);
@@ -934,7 +940,8 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
         /* No need to go into the guest when all we do is going out */
         if (signal_pending(current)) {
                 kvm_run->exit_reason = KVM_EXIT_INTR;
-                return -EINTR;
+                ret = -EINTR;
+                goto out;
         }
 
         /* Save FPU state in stack */
@@ -1004,6 +1011,8 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
         current->thread.used_vsr = used_vsr;
 #endif
 
+out:
+        preempt_enable();
         return ret;
 }