[PATCH v1] KVM: arm64: selftests: Handle feature fields with nonzero minimum value correctly

[Jing Zhang]

There are some feature fields with nonzero minimum valid value. Make
sure get_safe_value() won't return invalid field values for them.
Also fix a bug that wrongly uses the feature bits type as the feature
bits sign causing all fields as signed in the get_safe_value() and
get_invalid_value().

Fixes: 54a9ea73527d ("KVM: arm64: selftests: Test for setting ID register from usersapce")
Reported-by: Zenghui Yu <yuzenghui at huawei.com>
Reported-by: Itaru Kitayama <itaru.kitayama at linux.dev>
Signed-off-by: Jing Zhang <jingzhangos at google.com>
---
 .../selftests/kvm/aarch64/set_id_regs.c       | 20 +++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
index bac05210b539..f17454dc6d9e 100644
--- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
@@ -224,13 +224,20 @@ uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 {
 	uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
 
-	if (ftr_bits->type == FTR_UNSIGNED) {
+	if (ftr_bits->sign == FTR_UNSIGNED) {
 		switch (ftr_bits->type) {
 		case FTR_EXACT:
 			ftr = ftr_bits->safe_val;
 			break;
 		case FTR_LOWER_SAFE:
-			if (ftr > 0)
+			uint64_t min_safe = 0;
+
+			if (!strcmp(ftr_bits->name, "ID_AA64DFR0_EL1_DebugVer"))
+				min_safe = ID_AA64DFR0_EL1_DebugVer_IMP;
+			else if (!strcmp(ftr_bits->name, "ID_DFR0_EL1_CopDbg"))
+				min_safe = ID_DFR0_EL1_CopDbg_Armv8;
+
+			if (ftr > min_safe)
 				ftr--;
 			break;
 		case FTR_HIGHER_SAFE:
@@ -252,7 +259,12 @@ uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 			ftr = ftr_bits->safe_val;
 			break;
 		case FTR_LOWER_SAFE:
-			if (ftr > 0)
+			uint64_t min_safe = 0;
+
+			if (!strcmp(ftr_bits->name, "ID_DFR0_EL1_PerfMon"))
+				min_safe = ID_DFR0_EL1_PerfMon_PMUv3;
+
+			if (ftr > min_safe)
 				ftr--;
 			break;
 		case FTR_HIGHER_SAFE:
@@ -276,7 +288,7 @@ uint64_t get_invalid_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 {
 	uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
 
-	if (ftr_bits->type == FTR_UNSIGNED) {
+	if (ftr_bits->sign == FTR_UNSIGNED) {
 		switch (ftr_bits->type) {
 		case FTR_EXACT:
 			ftr = max((uint64_t)ftr_bits->safe_val + 1, ftr + 1);

base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a
-- 
2.43.0.472.g3155946c3a-goog