s390x/tcg: facilitites and instructions

Let's handle it just like KVM:
Depending on the model, this instruction may not be provided. When this instruction is not provided, it is checked for operand exception and privileged-opera- tion exception, and then is suppressed.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)

Quoted 6 lines · On Mon, 4 Dec 2017 15:01:44 +0100 David Hildenbrand <[email protected]> wrote:

Let's handle it just like KVM:
Depending on the model, this instruction may not be provided. When this instruction is not provided, it is checked for operand exception and privileged-opera- tion exception, and then is suppressed.

Quoted 7 lines

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)

Looks reasonable (does Linux use this at all?)

Let's just wire it up like KVM.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)

Quoted 9 lines · On Mon, 4 Dec 2017 15:01:45 +0100 David Hildenbrand <[email protected]> wrote:

Let's just wire it up like KVM.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)

So we would have generated an exception before if someone tried to enable channel measurements under tcg?

Quoted 13 lines · Cornelia Huck

Quoted 9 lines · On Mon, 4 Dec 2017 15:01:45 +0100 David Hildenbrand <[email protected]> wrote:

Let's just wire it up like KVM.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)  

Quoted 3 lines

So we would have generated an exception before if someone tried to enable channel measurements under tcg?

Yes, PGM_OPERATION should have been triggered.

Quoted 18 lines · On Mon, 4 Dec 2017 18:27:55 +0100 David Hildenbrand <[email protected]> wrote:

Quoted 16 lines · Cornelia Huck

Quoted 9 lines · On Mon, 4 Dec 2017 15:01:45 +0100 David Hildenbrand <[email protected]> wrote:

Let's just wire it up like KVM.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/helper.h      | 1 +
 target/s390x/insn-data.def | 1 +
 target/s390x/misc_helper.c | 9 +++++++++
 target/s390x/translate.c   | 7 +++++++
 4 files changed, 18 insertions(+)  

So we would have generated an exception before if someone tried to enable channel measurements under tcg?

Quoted 2 lines

Yes, PGM_OPERATION should have been triggered.

Next question: What happens now if we try to enable channel measurements? :)

Just like KVM does, we should suppress this instruction:
When this instruction is not provided, it is checked for privileged operation exception and the instruction is suppressed by the machine

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/insn-data.def | 1 +
 target/s390x/translate.c   | 7 +++++++
 2 files changed, 8 insertions(+)

I have no idea what that instruction does, but KVM seems to suppress it, setting cc=3 (and as it seems to be an io instruction, it should be protected). Let's do the same for TCG, so we're at least equal.

(it is used in the kernel for qdio, I wasn't even able to find the real
name of that instruction)

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/insn-data.def | 1 +
 target/s390x/translate.c   | 8 ++++++++
 2 files changed, 9 insertions(+)

It only provies the EXTRACT CPU TIME instruction. We can reuse the stpt

helper, which calculates the CPU timer value.

As the instruction is not priviledged, but we don't have a CPU timer

value in case of linux user, we simply fake the CPU timer to be 0.

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/cpu_models.c  |  1 +
 target/s390x/insn-data.def |  2 ++
 target/s390x/translate.c   | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+)

Quoted 1 line · On Mon, 4 Dec 2017 15:01:48 +0100 David Hildenbrand <[email protected]> wrote:

It only provies the EXTRACT CPU TIME instruction. We can reuse the stpt

s/provies/provides/

Quoted 3 lines

helper, which calculates the CPU timer value.

As the instruction is not priviledged, but we don't have a CPU timer

s/priviledged/privileged/

Quoted 2 lines

value in case of linux user, we simply fake the CPU timer to be 0.

There's probably nothing else we could do.

The Set-Program-Parameter facility (also known as Load-Program-Parameter faciliy) provides the LPP instruction used to load the program

parameter. We already implement that instruction in TCG, so add it to our list.

Note: Not documented in the PoP but in "The Load-Program-Parameter and CPU-Measurement Facilities) - SA23-2260-05 document.

While at it, make the whole list ordered (accoring to cpu_features_def.h).

Signed-off-by David Hildenbrand <[email protected]>

---
 target/s390x/cpu_models.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

We are good enough to boot upstream Linux kernels / Fedora 26/27. That should be suficient for now.

As the QEMU CPU model is migration safe, let's add compatibility code. Generate the feature list to reduce the trouble of messing things up in the future.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/s390x/s390-virtio-ccw.c  |   6 +++
 target/s390x/cpu.h          |   3 ++
 target/s390x/cpu_models.c   | 100 ++++++++++++++++++--------------------------
 target/s390x/cpu_models.h   |   1 +
 target/s390x/gen-features.c |  87 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 138 insertions(+), 59 deletions(-)

hw/s390x/s390-virtio-ccw.c +0 -0

index a23b8aec9f..edd18b7fac 100644

hw/s390x/s390-virtio-ccw.c +13 -0

 }
 
 static void ccw_machine_2_11_class_options(MachineClass *mc)

@@ -81,6 +80,11 @@ static S390CPUDef s390_cpu_defs[] = {
     CPUDEF_INIT(0x3906, 14, 1, 47, 0x08000000U, "z14", "IBM z14 GA1"),
 };
 
+static S390CPUDef s390_qemu_cpu_def;
+static S390CPUModel s390_qemu_cpu_model;
+
+/* Set the qemu CPU model (on machine initialization). Must not be called
+ * once CPUs have been created.
+ */
+void s390_set_qemu_cpu_model(uint16_t type, uint8_t gen, uint8_t ec_ga,
+                             const S390FeatBitmap features)
+{
+    const S390CPUDef *def = s390_find_cpu_def(type, gen, ec_ga, NULL);
+
+    g_assert(def);
+    g_assert(QTAILQ_EMPTY(&cpus));

hw/s390x/s390-virtio-ccw.c +9 -7

+    /* build the CPU model */
+    s390_qemu_cpu_model.def = &s390_qemu_cpu_def;
+    bitmap_copy(s390_qemu_cpu_model.features, features, S390_FEAT_MAX);
+}
+
 static void s390_qemu_cpu_model_initfn(Object *obj)
 {
-    static S390CPUDef s390_qemu_cpu_defs;
     S390CPU *cpu = S390_CPU(obj);
 
     cpu->model = g_malloc0(sizeof(*cpu->model));
-    /* TCG emulates a z900 (with some optional additional features) */
-    memcpy(&s390_qemu_cpu_defs, &s390_cpu_defs[0], sizeof(s390_qemu_cpu_defs));
-    add_qemu_cpu_model_features(s390_qemu_cpu_defs.full_feat);
-    cpu->model->def = &s390_qemu_cpu_defs;
-    bitmap_copy(cpu->model->features, cpu->model->def->default_feat,
-                S390_FEAT_MAX);
+    /* has to be initialized by now via s390_set_qemu_cpu_model() */
+    g_assert(s390_qemu_cpu_model.def);
+    /* copy the CPU model so we can modify it */
+    memcpy(cpu->model, &s390_qemu_cpu_model, sizeof(*cpu->model));
 }
 
 static void s390_cpu_model_finalize(Object *obj)

target/s390x/cpu_models.h +1 -0

index 4c6dee1871..11cf5386fb 100644
@@ -14,6 +14,7 @@
 #define TARGET_S390X_CPU_MODELS_H
 
 #include "cpu_features.h"
+#include "gen-features.h"
 #include "qom/cpu.h"
 
 /* static CPU definition */

target/s390x/gen-features.c +87 -0

index 68e6c31b4b..983f2dcd52 100644
@@ -536,6 +536,51 @@ static uint16_t default_GEN14_GA1[] = {
     S390_FEAT_GROUP_MSA_EXT_8,
 };
 
+/* QEMU (CPU model) features */
+
+static uint16_t qemu_V2_11[] = {
+    S390_FEAT_GROUP_PLO,
+    S390_FEAT_ESAN3,
+    S390_FEAT_ZARCH,
+};
+
+static uint16_t qemu_V2_12[] = {
+    S390_FEAT_DAT_ENH,
+    S390_FEAT_IDTE_SEGMENT,
+    S390_FEAT_STFLE,
+    S390_FEAT_SENSE_RUNNING_STATUS,
+    S390_FEAT_EXTENDED_TRANSLATION_2,
+    S390_FEAT_MSA,
+    S390_FEAT_LONG_DISPLACEMENT,
+    S390_FEAT_LONG_DISPLACEMENT_FAST,
+    S390_FEAT_EXTENDED_IMMEDIATE,
+    S390_FEAT_EXTENDED_TRANSLATION_3,
+    S390_FEAT_ETF2_ENH,
+    S390_FEAT_STORE_CLOCK_FAST,
+    S390_FEAT_MOVE_WITH_OPTIONAL_SPEC,
+    S390_FEAT_ETF3_ENH,
+    S390_FEAT_EXTRACT_CPU_TIME,
+    S390_FEAT_COMPARE_AND_SWAP_AND_STORE,
+    S390_FEAT_COMPARE_AND_SWAP_AND_STORE_2,
+    S390_FEAT_GENERAL_INSTRUCTIONS_EXT,
+    S390_FEAT_EXECUTE_EXT,
+    S390_FEAT_SET_PROGRAM_PARAMETERS,
+    S390_FEAT_FLOATING_POINT_SUPPPORT_ENH,
+    S390_FEAT_STFLE_45,
+    S390_FEAT_STFLE_49,
+    S390_FEAT_LOCAL_TLB_CLEARING,
+    S390_FEAT_INTERLOCKED_ACCESS_2,
+    S390_FEAT_STFLE_53,
+    S390_FEAT_MSA_EXT_4,
+    S390_FEAT_MSA_EXT_3,
+};
+
+/* add all new definitions before this point */
+static uint16_t qemu_MAX[] = {
+    /* generates a dependency warning, leave it out for now */
+    S390_FEAT_MSA_EXT_5,
+};
+
 /****** END FEATURE DEFS ******/
 
 #define _YEARS  "2016"

@@ -627,6 +672,24 @@ static FeatGroupDefSpec FeatGroupDef[] = {
     FEAT_GROUP_INITIALIZER(MSA_EXT_8),
 };
 
+#define QEMU_FEAT_INITIALIZER(_name)                   \
+    {                                                  \
+        .name = "S390_FEAT_LIST_QEMU_" #_name,         \
+        .bits =                                        \
+            { .data = qemu_##_name,                    \
+              .len = ARRAY_SIZE(qemu_##_name) },       \
+    }
+
+/*******************************
+ * QEMU (CPU model) features
+ *******************************/
+static FeatGroupDefSpec QemuFeatDef[] = {
+    QEMU_FEAT_INITIALIZER(V2_11),
+    QEMU_FEAT_INITIALIZER(V2_12),
+    QEMU_FEAT_INITIALIZER(MAX),
+};
+
+
 static void set_bits(uint64_t list[], BitSpec bits)
 {
     uint32_t i;

@@ -684,6 +747,29 @@ static void print_feature_defs(void)
     }
 }
 
+static void print_qemu_feature_defs(void)
+{
+    uint64_t feat[S390_FEAT_MAX / 64 + 1] = {};
+    int i, j;
+
+    printf("\n/* QEMU (CPU model) feature list data */\n");
+
+    /* for now we assume that we only add new features */
+    for (i = 0; i < ARRAY_SIZE(QemuFeatDef); i++) {
+        set_bits(feat, QemuFeatDef[i].bits);
+
+        printf("#define %s\t", QemuFeatDef[i].name);
+        for (j = 0; j < ARRAY_SIZE(feat); j++) {
+            printf("0x%016"PRIx64"ULL", feat[j]);
+            if (j < ARRAY_SIZE(feat) - 1) {
+                printf(",");
+            } else {
+                printf("\n");
+            }
+        }
+    }
+}
+
 static void print_feature_group_defs(void)
 {
     int i, j;

@@ -721,6 +807,7 @@ int main(int argc, char *argv[])
            "#ifndef %s\n#define %s\n", __FILE__, _YEARS, _NAME_H, _NAME_H);
     print_feature_defs();
     print_feature_group_defs();
+    print_qemu_feature_defs();
     printf("\n#endif\n");
     return 0;
 }

Quoted 2 lines · On Mon, 4 Dec 2017 15:01:50 +0100 David Hildenbrand <[email protected]> wrote:

We are good enough to boot upstream Linux kernels / Fedora 26/27. That should be suficient for now.

s/suficient/sufficient/

Quoted 4 lines

As the QEMU CPU model is migration safe, let's add compatibility code. Generate the feature list to reduce the trouble of messing things up in the future.

So we can mess up things effortlessly? :)

Quoted 17 lines

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/s390x/s390-virtio-ccw.c  |   6 +++
 target/s390x/cpu.h          |   3 ++
 target/s390x/cpu_models.c   | 100 ++++++++++++++++++--------------------------
 target/s390x/cpu_models.h   |   1 +
 target/s390x/gen-features.c |  87 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 138 insertions(+), 59 deletions(-)

hw/s390x/s390-virtio-ccw.c +0 -0

index a23b8aec9f..edd18b7fac 100644
@@ -721,6 +721,9 @@ bool css_migration_enabled(void)
 

hw/s390x/s390-virtio-ccw.c bool css_migration_enabled(void) · line 726

Quoted 5 lines

hw/s390x/s390-virtio-ccw.c +3 -0

 static void ccw_machine_2_12_instance_options(MachineState *machine)
 {
+    const S390FeatBitmap qemu_cpu_feat = { S390_FEAT_LIST_QEMU_V2_12 };
+
+    s390_set_qemu_cpu_model(0x2827, 12, 2, qemu_cpu_feat);

Does this want a comment?

Quoted 5 lines

hw/s390x/s390-virtio-ccw.c +5 -0

+
+    /* TCG emulates some features that can usually not be enabled with
+     * the emulated machine generation. Make sure they can be enabled
+     * when using the QEMU model by adding them to full_feat. We have
+     * to copy the definition to do that.

hw/s390x/s390-virtio-ccw.c

Quoted 5 lines

hw/s390x/s390-virtio-ccw.c +5 -0

+     */
+    memcpy(&s390_qemu_cpu_def, def, sizeof(s390_qemu_cpu_def));
+    bitmap_or(s390_qemu_cpu_def.full_feat, s390_qemu_cpu_def.full_feat,
+              qemu_max_cpu_feat, S390_FEAT_MAX);
+

So is this the place to e.g. enable zpci? Or does this need to go into the feature definitions?