On 3/10/26 8:05 AM, Markus Armbruster wrote:
> Nathan Chen <[email protected]> writes:
>
>> From: Nathan Chen <[email protected]>
>>
>> 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.
>>
>> Set the default value of ATS to auto. The default for ATS support used
>> to be set to off, but we change it to match what the host IOMMU
>> properties report.
>>
>> Add a "ats-enabled" read-only property for smmuv3 to address an
>> expected bool for the "ats" property in iort_smmuv3_devices().
>>
>> Signed-off-by: Nathan Chen <[email protected]>
>> ---
>> hw/arm/smmuv3-accel.c | 25 +++++++++++++++++++++++--
>> hw/arm/smmuv3.c | 12 ++++++++++--
>> hw/arm/virt-acpi-build.c | 2 +-
>> include/hw/arm/smmuv3.h | 2 +-
>> 4 files changed, 35 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
>> index 617629bacd..8fec335557 100644
>> --- a/hw/arm/smmuv3-accel.c
>> +++ b/hw/arm/smmuv3-accel.c
>> @@ -52,6 +52,12 @@ static void smmuv3_accel_auto_finalise(SMMUv3State *s,
>> PCIDevice *pdev,
>> return;
>> }
>>
>> + /* Update ATS if auto from info */
>> + 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;
>> }
>>
>> @@ -124,6 +130,13 @@ smmuv3_accel_check_hw_compatible(SMMUv3State *s,
>> smmuv3_oas_bits(FIELD_EX32(s->idr[5], IDR5, OAS)));
>> return false;
>> }
>> + /* Check ATS value opted is compatible with Host SMMUv3 */
>> + if (FIELD_EX32(info->idr[0], IDR0, ATS) <
>> + FIELD_EX32(s->idr[0], IDR0, ATS)) {
>> + error_setg(errp, "Host SMMUv3 doesn't support Address Translation"
>> + " Services");
>> + return false;
>> + }
>>
>> /* QEMU SMMUv3 supports GRAN4K/GRAN16K/GRAN64K translation granules */
>> if (FIELD_EX32(info->idr[5], IDR5, GRAN4K) !=
>> @@ -844,8 +857,12 @@ void smmuv3_accel_idr_override(SMMUv3State *s)
>> /* By default QEMU SMMUv3 has RIL. Update IDR3 if user has disabled it
>> */
>> s->idr[3] = FIELD_DP32(s->idr[3], IDR3, RIL, s->ril);
>>
>> - /* QEMU SMMUv3 has no ATS. Advertise ATS if opt-in by property */
>> - s->idr[0] = FIELD_DP32(s->idr[0], IDR0, ATS, s->ats);
>> + /* Only override ATS if user explicitly set ON or OFF */
>> + if (s->ats == ON_OFF_AUTO_ON) {
>> + s->idr[0] = FIELD_DP32(s->idr[0], IDR0, ATS, 1);
>> + } else if (s->ats == ON_OFF_AUTO_OFF) {
>> + s->idr[0] = FIELD_DP32(s->idr[0], IDR0, ATS, 0);
>> + }
>>
>> /* Advertise 48-bit OAS in IDR5 when requested (default is 44 bits). */
>> if (s->oas == SMMU_OAS_48BIT) {
>> @@ -923,4 +940,8 @@ void smmuv3_accel_init(SMMUv3State *s)
>> s->s_accel = g_new0(SMMUv3AccelState, 1);
>> bs->iommu_ops = &smmuv3_accel_ops;
>> smmuv3_accel_as_init(s);
>> +
>> + if (s->ats == ON_OFF_AUTO_AUTO) {
>> + s->s_accel->auto_mode = true;
>> + }
>> }
>> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
>> index 068108e49b..197ba7c77b 100644
>> --- a/hw/arm/smmuv3.c
>> +++ b/hw/arm/smmuv3.c
>> @@ -317,6 +317,12 @@ static void smmuv3_init_id_regs(SMMUv3State *s)
>> smmuv3_accel_idr_override(s);
>> }
>>
>> +static bool get_ats_enabled(Object *obj, Error **errp)
>> +{
>> + SMMUv3State *s = ARM_SMMUV3(obj);
>> + return FIELD_EX32(s->idr[0], IDR0, ATS);
>> +}
>> +
>> static void smmuv3_reset(SMMUv3State *s)
>> {
>> s->cmdq.base = deposit64(s->cmdq.base, 0, 5, SMMU_CMDQS);
>> @@ -1971,7 +1977,7 @@ static bool smmu_validate_property(SMMUv3State *s,
>> Error **errp)
>> error_setg(errp, "ril can only be disabled if accel=on");
>> return false;
>> }
>> - if (s->ats) {
>> + if (s->ats == ON_OFF_AUTO_ON) {
>> error_setg(errp, "ats can only be enabled if accel=on");
>> return false;
>> }
>> @@ -2128,7 +2134,7 @@ static const Property smmuv3_properties[] = {
>> DEFINE_PROP_UINT64("msi-gpa", SMMUv3State, msi_gpa, 0),
>> /* RIL can be turned off for accel cases */
>> DEFINE_PROP_BOOL("ril", SMMUv3State, ril, true),
>> - DEFINE_PROP_BOOL("ats", SMMUv3State, ats, false),
>> + DEFINE_PROP_ON_OFF_AUTO("ats", SMMUv3State, ats, ON_OFF_AUTO_AUTO),
> Is property "ats" accessible via QMP or JSON command line? If yes, this
> is an incompatible change: JSON values false and true no longer work.
So what do you recommend to extend the property values. I guess we had
some existing scenarios happening in the past. What is the best way to
proceed?
Eric
>
>> DEFINE_PROP_UINT8("oas", SMMUv3State, oas, 44),
>> DEFINE_PROP_UINT8("ssidsize", SMMUv3State, ssidsize, 0),
>> };
>> @@ -2153,6 +2159,8 @@ static void smmuv3_class_init(ObjectClass *klass,
>> const void *data)
>> dc->hotpluggable = false;
>> dc->user_creatable = true;
>>
>> + object_class_property_add_bool(klass, "ats-enabled", get_ats_enabled,
>> NULL);
>> +
>> object_class_property_set_description(klass, "accel",
>> "Enable SMMUv3 accelerator support. Allows host SMMUv3 to be "
>> "configured in nested mode for vfio-pci dev assignment");
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index 719d2f994e..6c77fc5f6a 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -402,7 +402,7 @@ static int iort_smmuv3_devices(Object *obj, void *opaque)
>>
>> bus = PCI_BUS(object_property_get_link(obj, "primary-bus",
>> &error_abort));
>> sdev.accel = object_property_get_bool(obj, "accel", &error_abort);
>> - sdev.ats = object_property_get_bool(obj, "ats", &error_abort);
>> + sdev.ats = object_property_get_bool(obj, "ats-enabled", &error_abort);
>> pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
>> sbdev = SYS_BUS_DEVICE(obj);
>> sdev.base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
>> diff --git a/include/hw/arm/smmuv3.h b/include/hw/arm/smmuv3.h
>> index 26b2fc42fd..2ca49ded36 100644
>> --- a/include/hw/arm/smmuv3.h
>> +++ b/include/hw/arm/smmuv3.h
>> @@ -70,7 +70,7 @@ struct SMMUv3State {
>> uint64_t msi_gpa;
>> Error *migration_blocker;
>> bool ril;
>> - bool ats;
>> + OnOffAuto ats;
>> uint8_t oas;
>> uint8_t ssidsize;
>> };
