KVM: PPC: Inform the userspace about TCE update failures

We return H_TOO_HARD from TCE update handlers when we think that
the next handler (realmode -> virtual mode -> user mode) has a chance to
handle the request; H_HARDWARE/H_CLOSED otherwise.

This changes the handlers to return H_TOO_HARD on every error giving
the userspace an opportunity to handle any request or at least log
them all.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kvm/book3s_64_vio.c

@@ -401,7 +401,7 @@ static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
 	long ret;
 
 	if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir)))
-		return H_HARDWARE;
+		return H_TOO_HARD;
 
 	if (dir == DMA_NONE)
 		return H_SUCCESS;
@@ -449,15 +449,15 @@ long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
 		return H_TOO_HARD;
 
 	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
-		return H_HARDWARE;
+		return H_TOO_HARD;
 
 	if (mm_iommu_mapped_inc(mem))
-		return H_CLOSED;
+		return H_TOO_HARD;
 
 	ret = iommu_tce_xchg(tbl, entry, &hpa, &dir);
 	if (WARN_ON_ONCE(ret)) {
 		mm_iommu_mapped_dec(mem);
-		return H_HARDWARE;
+		return H_TOO_HARD;
 	}
 
 	if (dir != DMA_NONE)

arch/powerpc/kvm/book3s_64_vio_hv.c

@@ -300,10 +300,10 @@ static long kvmppc_rm_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
 
 	if (WARN_ON_ONCE_RM(mm_iommu_ua_to_hpa_rm(mem, ua, tbl->it_page_shift,
 			&hpa)))
-		return H_HARDWARE;
+		return H_TOO_HARD;
 
 	if (WARN_ON_ONCE_RM(mm_iommu_mapped_inc(mem)))
-		return H_CLOSED;
+		return H_TOO_HARD;
 
 	ret = iommu_tce_xchg_rm(kvm->mm, tbl, entry, &hpa, &dir);
 	if (ret) {
@@ -501,7 +501,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 
 		rmap = (void *) vmalloc_to_phys(rmap);
 		if (WARN_ON_ONCE_RM(!rmap))
-			return H_HARDWARE;
+			return H_TOO_HARD;
 
 		/*
 		 * Synchronize with the MMU notifier callbacks in