KVM: arm64: selftests: Handle feature fields with nonzero minimum value correctly

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@huawei.com>
Reported-by: Itaru Kitayama <itaru.kitayama@linux.dev>
Tested-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20240115220210.3966064-2-jingzhangos@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
index bac05210b53927970eb91cbac3e985b8ba74c897..16e2338686c172c1e1ece67e405df3ab666f7ded 100644 (file)
--- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
@@ -32,6 +32,10 @@ struct reg_ftr_bits {
        enum ftr_type type;
        uint8_t shift;
        uint64_t mask;
+       /*
+        * For FTR_EXACT, safe_val is used as the exact safe value.
+        * For FTR_LOWER_SAFE, safe_val is used as the minimal safe value.
+        */
        int64_t safe_val;
 };
 
@@ -65,13 +69,13 @@ struct test_feature_reg {
 
 static const struct reg_ftr_bits ftr_id_aa64dfr0_el1[] = {
        S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, PMUVer, 0),
-       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, DebugVer, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, DebugVer, ID_AA64DFR0_EL1_DebugVer_IMP),
        REG_FTR_END,
 };
 
 static const struct reg_ftr_bits ftr_id_dfr0_el1[] = {
-       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, PerfMon, 0),
-       REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, CopDbg, 0),
+       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, PerfMon, ID_DFR0_EL1_PerfMon_PMUv3),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, CopDbg, ID_DFR0_EL1_CopDbg_Armv8),
        REG_FTR_END,
 };
 
@@ -224,13 +228,13 @@ 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)
+                       if (ftr > ftr_bits->safe_val)
                                ftr--;
                        break;
                case FTR_HIGHER_SAFE:
@@ -252,7 +256,7 @@ 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)
+                       if (ftr > ftr_bits->safe_val)
                                ftr--;
                        break;
                case FTR_HIGHER_SAFE:
@@ -276,7 +280,7 @@ 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);