[PATCH 19/52] KVM: PPC: Book3s: PR: Disable preemption in vcpu_run

Alexander Graf
2012-01-13T14:31:22Z

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>
---
arch/powerpc/kvm/book3s_pr.c | 13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 203a7b7..19af2bf 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;
}

--
1.6.0.2