KVM: PPC: Use get/set for to_svcpu to help preemption
When running the 64-bit Book3s PR code without CONFIG_PREEMPT_NONE, we were
doing a few things wrong, most notably access to PACA fields without making
sure that the pointers stay stable accross the access (preempt_disable()).
This patch moves to_svcpu towards a get/put model which allows us to disable
preemption while accessing the shadow vcpu fields in the PACA. That way we
can run preemptible and everyone's happy!
Reported-by: Jörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 0c9dc62..f1950d1 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -230,9 +230,12 @@
r = kvmppc_st(vcpu, &addr, 32, zeros, true);
if ((r == -ENOENT) || (r == -EPERM)) {
+ struct kvmppc_book3s_shadow_vcpu *svcpu;
+
+ svcpu = svcpu_get(vcpu);
*advance = 0;
vcpu->arch.shared->dar = vaddr;
- to_svcpu(vcpu)->fault_dar = vaddr;
+ svcpu->fault_dar = vaddr;
dsisr = DSISR_ISSTORE;
if (r == -ENOENT)
@@ -241,7 +244,8 @@
dsisr |= DSISR_PROTFAULT;
vcpu->arch.shared->dsisr = dsisr;
- to_svcpu(vcpu)->fault_dsisr = dsisr;
+ svcpu->fault_dsisr = dsisr;
+ svcpu_put(svcpu);
kvmppc_book3s_queue_irqprio(vcpu,
BOOK3S_INTERRUPT_DATA_STORAGE);