[PATCH v4 5/8] hw/arm/smmuv3-accel: Change SSIDSIZE property to SsidSizeMode

[Nathan Chen <nathanc@nvidia.com>]

From: Nathan Chen <nathanc@nvidia.com>

Change accel SMMUv3 SSIDSIZE property from uint8_t to SsidSizeMode.
The 'auto' value is not implemented, as this commit is meant to set the
property to the correct type and avoid breaking JSON/QMP when the auto
mode is introduced. A future patch will implement resolution of 'auto'
value to match the host SMMUv3 SSIDSIZE value.

Fixes: b8c6f8a69d27 ("hw/arm/smmuv3-accel: Make SubstreamID support configurable")
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Nathan Chen <nathanc@nvidia.com>
---
 hw/arm/smmuv3-accel.c          | 23 +++++++++++++++++++++--
 hw/arm/smmuv3.c                | 19 ++++++++++---------
 include/hw/arm/smmuv3-common.h |  1 -
 include/hw/arm/smmuv3.h        |  3 ++-
 4 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
index c31b64295e..bc6cbfebc2 100644
--- a/hw/arm/smmuv3-accel.c
+++ b/hw/arm/smmuv3-accel.c
@@ -802,7 +802,7 @@ static uint64_t smmuv3_accel_get_viommu_flags(void *opaque)
     SMMUState *bs = opaque;
     SMMUv3State *s = ARM_SMMUV3(bs);
 
-    if (s->ssidsize) {
+    if (s->ssidsize > SSID_SIZE_MODE_0) {
         flags |= VIOMMU_FLAG_PASID_SUPPORTED;
     }
     return flags;
@@ -817,6 +817,22 @@ static const PCIIOMMUOps smmuv3_accel_ops = {
     .get_msi_direct_gpa = smmuv3_accel_get_msi_gpa,
 };
 
+/*
+ * This returns the value of a SsidSizeMode value offset by 1 to
+ * account for the enum values offset by 1 from actual values.
+ *
+ * SSID_SIZE_MODE_0 = 1, SSID_SIZE_MODE_1 = 2, etc. so return 0
+ * if SSID_SIZE_MODE_0 is passed as input, return 1 if
+ * SSID_SIZE_MODE_1 is passed as input, etc.
+ */
+static uint8_t ssidsize_mode_to_value(SsidSizeMode mode)
+{
+    if (mode == SSID_SIZE_MODE_AUTO) {
+        return 0;
+    }
+    return mode - 1;
+}
+
 void smmuv3_accel_idr_override(SMMUv3State *s)
 {
     if (!s->accel) {
@@ -842,7 +858,10 @@ void smmuv3_accel_idr_override(SMMUv3State *s)
      * By default QEMU SMMUv3 has no SubstreamID support. Update IDR1 if user
      * has enabled it.
      */
-    s->idr[1] = FIELD_DP32(s->idr[1], IDR1, SSIDSIZE, s->ssidsize);
+    if (s->ssidsize > SSID_SIZE_MODE_0) {
+        s->idr[1] = FIELD_DP32(s->idr[1], IDR1, SSIDSIZE,
+                               ssidsize_mode_to_value(s->ssidsize));
+    }
 }
 
 /* Based on SMUUv3 GPBA.ABORT configuration, attach a corresponding HWPT */
diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index ea285bdf64..79018f8d66 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -20,6 +20,7 @@
 #include "qemu/bitops.h"
 #include "hw/core/irq.h"
 #include "hw/core/sysbus.h"
+#include "hw/core/qdev-properties-system.h"
 #include "migration/blocker.h"
 #include "migration/vmstate.h"
 #include "hw/core/qdev-properties.h"
@@ -625,7 +626,7 @@ static int decode_ste(SMMUv3State *s, SMMUTransCfg *cfg,
     }
 
     /* Multiple context descriptors require SubstreamID support */
-    if (!s->ssidsize && STE_S1CDMAX(ste) != 0) {
+    if (s->ssidsize == SSID_SIZE_MODE_0 && STE_S1CDMAX(ste) != 0) {
         qemu_log_mask(LOG_UNIMP,
                 "SMMUv3: multiple S1 context descriptors require SubstreamID support. "
                 "Configure ssidsize > 0 (requires accel=on)\n");
@@ -1979,6 +1980,10 @@ static bool smmu_validate_property(SMMUv3State *s, Error **errp)
         error_setg(errp, "ril auto mode is not supported");
         return false;
     }
+    if (s->ssidsize == SSID_SIZE_MODE_AUTO) {
+        error_setg(errp, "ssidsize auto mode is not supported");
+        return false;
+    }
 
     if (!s->accel) {
         if (s->ril == ON_OFF_AUTO_OFF) {
@@ -1993,7 +1998,7 @@ static bool smmu_validate_property(SMMUv3State *s, Error **errp)
             error_setg(errp, "OAS must be 44 bits when accel=off");
             return false;
         }
-        if (s->ssidsize) {
+        if (s->ssidsize > SSID_SIZE_MODE_0) {
             error_setg(errp, "ssidsize can only be set if accel=on");
             return false;
         }
@@ -2011,11 +2016,6 @@ static bool smmu_validate_property(SMMUv3State *s, Error **errp)
         error_setg(errp, "OAS can only be set to 44 or 48 bits");
         return false;
     }
-    if (s->ssidsize > SMMU_SSID_MAX_BITS) {
-        error_setg(errp, "ssidsize must be in the range 0 to %d",
-                   SMMU_SSID_MAX_BITS);
-        return false;
-    }
 
     return true;
 }
@@ -2144,7 +2144,8 @@ static const Property smmuv3_properties[] = {
     DEFINE_PROP_ON_OFF_AUTO("ril", SMMUv3State, ril, ON_OFF_AUTO_ON),
     DEFINE_PROP_ON_OFF_AUTO("ats", SMMUv3State, ats, ON_OFF_AUTO_OFF),
     DEFINE_PROP_UINT8("oas", SMMUv3State, oas, 44),
-    DEFINE_PROP_UINT8("ssidsize", SMMUv3State, ssidsize, 0),
+    DEFINE_PROP_SSIDSIZE_MODE("ssidsize", SMMUv3State, ssidsize,
+                              SSID_SIZE_MODE_0),
 };
 
 static void smmuv3_instance_init(Object *obj)
@@ -2185,7 +2186,7 @@ static void smmuv3_class_init(ObjectClass *klass, const void *data)
         "A value of N allows SSIDs in the range [0 .. 2^N - 1]. "
         "Valid range is 0-20, where 0 disables SubstreamID support. "
         "Defaults to 0. A value greater than 0 is required to enable "
-        "PASID support.");
+        "PASID support. ssidsize=auto is not supported.");
 }
 
 static int smmuv3_notify_flag_changed(IOMMUMemoryRegion *iommu,
diff --git a/include/hw/arm/smmuv3-common.h b/include/hw/arm/smmuv3-common.h
index 9f78bbe89e..7f0f992dfd 100644
--- a/include/hw/arm/smmuv3-common.h
+++ b/include/hw/arm/smmuv3-common.h
@@ -311,7 +311,6 @@ REG32(IDR1,                0x4)
     FIELD(IDR1, TABLES_PRESET, 30, 1)
     FIELD(IDR1, ECMDQ,        31, 1)
 
-#define SMMU_SSID_MAX_BITS 20
 #define SMMU_IDR1_SIDSIZE 16
 #define SMMU_CMDQS   19
 #define SMMU_EVENTQS 19
diff --git a/include/hw/arm/smmuv3.h b/include/hw/arm/smmuv3.h
index c35e599bbc..ddf472493d 100644
--- a/include/hw/arm/smmuv3.h
+++ b/include/hw/arm/smmuv3.h
@@ -21,6 +21,7 @@
 
 #include "hw/arm/smmu-common.h"
 #include "qom/object.h"
+#include "qapi/qapi-types-misc-arm.h"
 
 #define TYPE_SMMUV3_IOMMU_MEMORY_REGION "smmuv3-iommu-memory-region"
 
@@ -72,7 +73,7 @@ struct SMMUv3State {
     OnOffAuto ril;
     OnOffAuto ats;
     uint8_t oas;
-    uint8_t ssidsize;
+    SsidSizeMode ssidsize;
 };
 
 typedef enum {
-- 
2.43.0