powerpc/64s/pseries: Fix hash tlbiel_all_isa300 for guest kernels

tlbiel_all() can not be usable in !HVMODE when running hash presently,
remove HV privileged flushes when running in guest to make it usable.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126102530.691335-3-npiggin@gmail.com

Author: npiggin

arch/powerpc/mm/book3s64/hash_native.c

@@ -92,16 +92,15 @@ static void tlbiel_all_isa300(unsigned int num_sets, unsigned int is)
 	asm volatile("ptesync": : :"memory");
 
 	/*
-	 * Flush the first set of the TLB, and any caching of partition table
-	 * entries. Then flush the remaining sets of the TLB. Hash mode uses
-	 * partition scoped TLB translations.
+	 * Flush the partition table cache if this is HV mode.
 	 */
-	tlbiel_hash_set_isa300(0, is, 0, 2, 0);
-	for (set = 1; set < num_sets; set++)
-		tlbiel_hash_set_isa300(set, is, 0, 0, 0);
+	if (early_cpu_has_feature(CPU_FTR_HVMODE))
+		tlbiel_hash_set_isa300(0, is, 0, 2, 0);
 
 	/*
-	 * Now invalidate the process table cache.
+	 * Now invalidate the process table cache. UPRT=0 HPT modes (what
+	 * current hardware implements) do not use the process table, but
+	 * add the flushes anyway.
 	 *
 	 * From ISA v3.0B p. 1078:
 	 *     The following forms are invalid.
@@ -110,6 +109,14 @@ static void tlbiel_all_isa300(unsigned int num_sets, unsigned int is)
 	 */
 	tlbiel_hash_set_isa300(0, is, 0, 2, 1);
 
+	/*
+	 * Then flush the sets of the TLB proper. Hash mode uses
+	 * partition scoped TLB translations, which may be flushed
+	 * in !HV mode.
+	 */
+	for (set = 0; set < num_sets; set++)
+		tlbiel_hash_set_isa300(set, is, 0, 0, 0);
+
 	ppc_after_tlbiel_barrier();
 
 	asm volatile(PPC_ISA_3_0_INVALIDATE_ERAT "; isync" : : :"memory");