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/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 69c7377d..c941c21 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -183,7 +183,9 @@
static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
{
if ( num < 14 ) {
- to_svcpu(vcpu)->gpr[num] = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->gpr[num] = val;
+ svcpu_put(svcpu);
to_book3s(vcpu)->shadow_vcpu->gpr[num] = val;
} else
vcpu->arch.gpr[num] = val;
@@ -191,80 +193,120 @@
static inline ulong kvmppc_get_gpr(struct kvm_vcpu *vcpu, int num)
{
- if ( num < 14 )
- return to_svcpu(vcpu)->gpr[num];
- else
+ if ( num < 14 ) {
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong r = svcpu->gpr[num];
+ svcpu_put(svcpu);
+ return r;
+ } else
return vcpu->arch.gpr[num];
}
static inline void kvmppc_set_cr(struct kvm_vcpu *vcpu, u32 val)
{
- to_svcpu(vcpu)->cr = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->cr = val;
+ svcpu_put(svcpu);
to_book3s(vcpu)->shadow_vcpu->cr = val;
}
static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->cr;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ u32 r;
+ r = svcpu->cr;
+ svcpu_put(svcpu);
+ return r;
}
static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, u32 val)
{
- to_svcpu(vcpu)->xer = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->xer = val;
to_book3s(vcpu)->shadow_vcpu->xer = val;
+ svcpu_put(svcpu);
}
static inline u32 kvmppc_get_xer(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->xer;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ u32 r;
+ r = svcpu->xer;
+ svcpu_put(svcpu);
+ return r;
}
static inline void kvmppc_set_ctr(struct kvm_vcpu *vcpu, ulong val)
{
- to_svcpu(vcpu)->ctr = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->ctr = val;
+ svcpu_put(svcpu);
}
static inline ulong kvmppc_get_ctr(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->ctr;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong r;
+ r = svcpu->ctr;
+ svcpu_put(svcpu);
+ return r;
}
static inline void kvmppc_set_lr(struct kvm_vcpu *vcpu, ulong val)
{
- to_svcpu(vcpu)->lr = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->lr = val;
+ svcpu_put(svcpu);
}
static inline ulong kvmppc_get_lr(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->lr;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong r;
+ r = svcpu->lr;
+ svcpu_put(svcpu);
+ return r;
}
static inline void kvmppc_set_pc(struct kvm_vcpu *vcpu, ulong val)
{
- to_svcpu(vcpu)->pc = val;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ svcpu->pc = val;
+ svcpu_put(svcpu);
}
static inline ulong kvmppc_get_pc(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->pc;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong r;
+ r = svcpu->pc;
+ svcpu_put(svcpu);
+ return r;
}
static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
{
ulong pc = kvmppc_get_pc(vcpu);
- struct kvmppc_book3s_shadow_vcpu *svcpu = to_svcpu(vcpu);
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ u32 r;
/* Load the instruction manually if it failed to do so in the
* exit path */
if (svcpu->last_inst == KVM_INST_FETCH_FAILED)
kvmppc_ld(vcpu, &pc, sizeof(u32), &svcpu->last_inst, false);
- return svcpu->last_inst;
+ r = svcpu->last_inst;
+ svcpu_put(svcpu);
+ return r;
}
static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
{
- return to_svcpu(vcpu)->fault_dar;
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong r;
+ r = svcpu->fault_dar;
+ svcpu_put(svcpu);
+ return r;
}
static inline bool kvmppc_critical_section(struct kvm_vcpu *vcpu)