[PATCH v3 2/7] hw/arm/smmuv3-accel: Implement "auto" value for "ats"

[Nathan Chen <nathanc@nvidia.com>]

From: Nathan Chen <nathanc@nvidia.com>

Allow accelerated SMMUv3 Address Translation Services support property
to be derived from host IOMMU capabilities. Derive host values using
IOMMU_GET_HW_INFO, retrieving ATS capability from IDR0.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Nathan Chen <nathanc@nvidia.com>
---
 hw/arm/smmuv3-accel.c |  9 +++++++++
 hw/arm/smmuv3.c       | 11 ++++-------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
index 82c0800f4d..9fbd13c438 100644
--- a/hw/arm/smmuv3-accel.c
+++ b/hw/arm/smmuv3-accel.c
@@ -52,6 +52,11 @@ static void smmuv3_accel_auto_finalise(SMMUv3State *s,
         return;
     }
 
+    if (s->ats == ON_OFF_AUTO_AUTO) {
+        s->idr[0] = FIELD_DP32(s->idr[0], IDR0, ATS,
+                               FIELD_EX32(info->idr[0], IDR0, ATS));
+    }
+
     accel->auto_finalised = true;
 }
 
@@ -964,6 +969,10 @@ bool smmuv3_accel_init(SMMUv3State *s, Error **errp)
     bs->iommu_ops = &smmuv3_accel_ops;
     smmuv3_accel_as_init(s);
 
+    if (s->ats == ON_OFF_AUTO_AUTO) {
+        s->s_accel->auto_mode = true;
+    }
+
     if (s->s_accel->auto_mode) {
         s->machine_done.notify = smmuv3_machine_done;
         qemu_add_machine_init_done_notifier(&s->machine_done);
diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 5c2855c377..e558f09652 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -1965,10 +1965,6 @@ static void smmu_reset_exit(Object *obj, ResetType type)
 
 static bool smmu_validate_property(SMMUv3State *s, Error **errp)
 {
-    if (s->ats == ON_OFF_AUTO_AUTO) {
-        error_setg(errp, "ats auto mode is not supported");
-        return false;
-    }
     if (s->ril == ON_OFF_AUTO_AUTO) {
         error_setg(errp, "ril auto mode is not supported");
         return false;
@@ -2170,9 +2166,10 @@ static void smmuv3_class_init(ObjectClass *klass, const void *data)
         "Disable range invalidation support (for accel=on). ril=auto "
         "is not supported.");
     object_class_property_set_description(klass, "ats",
-        "Enable/disable ATS support (for accel=on). Please ensure host "
-        "platform has ATS support before enabling this. ats=auto is not "
-        "supported.");
+        "Enable/disable ATS support (for accel=on). "
+        "Valid values are on, off, and auto. Defaults to off. "
+        "Please ensure host platform supports ATS before setting it "
+        "to on.");
     object_class_property_set_description(klass, "oas",
         "Specify Output Address Size (for accel=on). Supported values "
         "are 44 or 48 bits. Defaults to 44 bits. oas=auto is not "
-- 
2.43.0