> -----Original Message-----
> From: Nathan Chen <[email protected]>
> Sent: 17 March 2026 18:38
> To: [email protected]; [email protected]
> Cc: Eric Auger <[email protected]>; Peter Maydell
> <[email protected]>; Shannon Zhao <[email protected]>;
> Michael S . Tsirkin <[email protected]>; Igor Mammedov
> <[email protected]>; Ani Sinha <[email protected]>; Paolo Bonzini
> <[email protected]>; Daniel P . Berrangé <[email protected]>; Eric
> Blake <[email protected]>; Markus Armbruster <[email protected]>;
> Shameer Kolothum Thodi <[email protected]>; Matt Ochs
> <[email protected]>; Nicolin Chen <[email protected]>; Nathan Chen
> <[email protected]>
> Subject: [PATCH v3 2/8] hw/arm/smmuv3-accel: Change ATS property to
> OnOffAuto
>
> From: Nathan Chen <[email protected]>
>
> Change accel SMMUv3 ATS property from bool to OnOffAuto. 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 the 'auto'
> value to match the host SMMUv3 ATS support.
>
> Fixes: f7f5013a55a3 ("hw/arm/smmuv3-accel: Add support for ATS")
> Signed-off-by: Nathan Chen <[email protected]>
> ---
> hw/arm/smmuv3-accel.c | 6 ++++--
> hw/arm/smmuv3.c | 14 ++++++++++++--
> hw/arm/virt-acpi-build.c | 2 +-
> include/hw/arm/smmuv3.h | 4 +++-
> 4 files changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
> index 2bb142c47f..621ac531a5 100644
> --- a/hw/arm/smmuv3-accel.c
> +++ b/hw/arm/smmuv3-accel.c
> @@ -826,8 +826,10 @@ 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 */
> + if (s->ats == ON_OFF_AUTO_ON) {
> + s->idr[0] = FIELD_DP32(s->idr[0], IDR0, ATS, 1);
> + }
Nit: I think we can keep the original comment.
>
> /* Advertise 48-bit OAS in IDR5 when requested (default is 44 bits). */
> if (s->oas == SMMU_OAS_48BIT) {
> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
> index 068108e49b..3dead0bcd3 100644
> --- a/hw/arm/smmuv3.c
> +++ b/hw/arm/smmuv3.c
> @@ -317,6 +317,11 @@ static void smmuv3_init_id_regs(SMMUv3State *s)
> smmuv3_accel_idr_override(s);
> }
>
> +bool smmuv3_ats_enabled(SMMUv3State *s)
> +{
> + 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 +1976,7 @@ 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;
> }
> @@ -1993,6 +1998,11 @@ static bool
> smmu_validate_property(SMMUv3State *s, Error **errp)
> return false;
> }
>
> + if (s->ats == ON_OFF_AUTO_AUTO) {
> + error_setg(errp, "ats cannot be set to auto");
> + return false;
> + }
Nit: Is "ats auto mode not supported" better?
Also, should we do this before the if (!s->accel) check above?
Otherwise, I think it will carry on for non-accel smmuv3 cases like,
-device arm-smmuv3,primary-bus=pcie.1,accel=off,ats=auto
I think this applies to other properties in this series as well.
> if (s->oas != SMMU_OAS_44BIT && s->oas != SMMU_OAS_48BIT) {
> error_setg(errp, "OAS can only be set to 44 or 48 bits");
> return false;
> @@ -2128,7 +2138,7 @@ 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_OFF),
I think we should update the description in
object_class_property_set_description
to mention auto not supported.
Thanks,
Shameer
> DEFINE_PROP_UINT8("oas", SMMUv3State, oas, 44),
> DEFINE_PROP_UINT8("ssidsize", SMMUv3State, ssidsize, 0),
> };
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 719d2f994e..591cfc993c 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 = smmuv3_ats_enabled(ARM_SMMUV3(obj));
> 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..ce51a5b9b4 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;
> };
> @@ -91,6 +91,8 @@ struct SMMUv3Class {
> ResettablePhases parent_phases;
> };
>
> +bool smmuv3_ats_enabled(struct SMMUv3State *s);
> +
> #define TYPE_ARM_SMMUV3 "arm-smmuv3"
> OBJECT_DECLARE_TYPE(SMMUv3State, SMMUv3Class, ARM_SMMUV3)
>
> --
> 2.43.0
