> -----Original Message-----
> From: Nathan Chen <[email protected]>
> Sent: 12 May 2026 20:35
> To: [email protected]; [email protected]
> Cc: Eric Auger <[email protected]>; Peter Maydell
> <[email protected]>; Philippe Mathieu-Daudé <[email protected]>;
> Zhao Liu <[email protected]>; Matt Ochs <[email protected]>; Nicolin
> Chen <[email protected]>; Shameer Kolothum Thodi
> <[email protected]>; Nathan Chen <[email protected]>
> Subject: [PATCH v3 2/7] hw/arm/smmuv3-accel: Implement "auto" value for
> "ats"
>
> 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.
>
> Reviewed-by: Eric Auger <[email protected]>
> Signed-off-by: Nathan Chen <[email protected]>
> ---
> 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 "
In smmuv3.c we have;
case SMMU_CMD_ATC_INV:
{
SMMUDevice *sdev = smmu_find_sdev(bs, CMD_SID(&cmd));
if (!sdev || !s->ats) {
trace_smmuv3_unhandled_cmd(type);
break;
}
if (!smmuv3_accel_issue_inv_cmd(s, &cmd, sdev, errp)) {
cmd_error = SMMU_CERROR_ILL;
break;
}
break;
}
The above !s->ats will be true for AUTO case, right? I think
we should change the above check with smmuv3_ats_enabled().
Also, since we modified the ats to OnOffAuto in the previous
series, I am not sure the above should be a fix patch or not.
Thanks,
Shameer
