KVM: PPC: Book3S PR: Add guard code to prevent returning to guest with PR=0 and Transactional state

Currently PR KVM doesn't support transaction memory in guest privileged
state.

This patch adds a check at setting guest msr, so that we can never return
to guest with PR=0 and TS=0b10. A tabort will be emulated to indicate
this and fail transaction immediately.

[paulus@ozlabs.org - don't change the TM_CAUSE_MISC definition, instead
 use TM_CAUSE_KVM_FAC_UNAV.]

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s.h

@@ -31,4 +31,10 @@ extern int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu,
 extern int kvmppc_book3s_init_pr(void);
 extern void kvmppc_book3s_exit_pr(void);
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+extern void kvmppc_emulate_tabort(struct kvm_vcpu *vcpu, int ra_val);
+#else
+static inline void kvmppc_emulate_tabort(struct kvm_vcpu *vcpu, int ra_val) {}
+#endif
+
 #endif