@samitouri / QOSamiQemu / commits / 16c547e9cb

hw/arm/smmuv3-accel: Add helper for resolving auto parameters

Introduce smmuv3_accel_auto_finalise() to resolve properties that are set to 'auto' for accelerated SMMUv3. This helper function allows properties such as ats, ril, ssidsize, and oas support to be resolved from host IOMMU capabilities via IOMMU_GET_HW_INFO. The later commits in this series set the auto_mode flag to true when an accel SMMUv3 property value is explicitly set to 'auto', or if the property value is not set and defaults to auto mode. Setting these property values to 'auto' requires at least one cold-plugged device to retrieve and finalise these properties. If the auto_mode flag is true, register a machine_init_done notifier to verify this requirement and fail boot if it is not met. Hot-plugged devices into an accel SMMUv3-associated bus will re-use the resolved host values from the initial cold-plug. Subsequent patches will make use of this helper to resolve 'auto' to what is reported by host IOMMU capabilities. Suggested-by: Shameer Kolothum <skolothumtho@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Shameer Kolothum <skolothumtho@nvidia.com> Signed-off-by: Nathan Chen <nathanc@nvidia.com> Tested-by: Eric Auger <eric.auger@redhat.com> Message-id: 20260608174900.2227340-4-nathanc@nvidia.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Nathan Chen committed Jun 8, 2026 at 10:48 UTC 16c547e9cb911d751d35fbe181a5cea8f9d52fbc
3 files changed +46
hw/arm/smmuv3-accel.c
+41
@@ -18,6 +18,7 @@
18
19 #include "smmuv3-internal.h"
20 #include "smmuv3-accel.h"
21 +#include "system/system.h"
22
23 /*
24 * The root region aliases the global system memory, and shared_as_sysmem
@@ -35,11 +36,33 @@ static int smmuv3_oas_bits(uint32_t oas)
36 return map[oas];
37 }
38
39 +static void smmuv3_accel_auto_finalise(SMMUv3State *s,
40 + struct iommu_hw_info_arm_smmuv3 *info)
41 +{
42 + SMMUv3AccelState *accel = s->s_accel;
43 +
44 + /*
45 + * Return if 'auto' was not set for any accel SMMUv3 property, or
46 + * if property values were already resolved from a previous call
47 + * to this function (e.g. if this function was called again after
48 + * VM boot during device hot plug). We do not accept new property
49 + * values in this case where auto_finalised == true, and we re-use
50 + * the values determined from the initial cold plug.
51 + */
52 + if (!accel->auto_mode || accel->auto_finalised) {
53 + return;
54 + }
55 +
56 + accel->auto_finalised = true;
57 +}
58 +
59 static bool
60 smmuv3_accel_check_hw_compatible(SMMUv3State *s,
61 struct iommu_hw_info_arm_smmuv3 *info,
62 Error **errp)
63 {
64 + smmuv3_accel_auto_finalise(s, info);
65 +
66 /* QEMU SMMUv3 supports both linear and 2-level stream tables */
67 if (FIELD_EX32(info->idr[0], IDR0, STLEVEL) !=
68 FIELD_EX32(s->idr[0], IDR0, STLEVEL)) {
@@ -918,6 +941,18 @@ static void smmuv3_accel_as_init(SMMUv3State *s)
941 address_space_init(shared_as_sysmem, &root, "smmuv3-accel-as-sysmem");
942 }
943
944 +static void smmuv3_accel_machine_done(Notifier *notifier, void *data)
945 +{
946 + SMMUv3State *s = container_of(notifier, SMMUv3State, machine_done);
947 + SMMUv3AccelState *accel = s->s_accel;
948 +
949 + if (accel->auto_mode && !accel->auto_finalised) {
950 + error_report("arm-smmuv3 accel=on with 'auto' properties requires "
951 + "at least one cold-plugged VFIO device");
952 + exit(1);
953 + }
954 +}
955 +
956 bool smmuv3_accel_init(SMMUv3State *s, Error **errp)
957 {
958 SMMUState *bs = ARM_SMMU(s);
@@ -925,5 +960,11 @@ bool smmuv3_accel_init(SMMUv3State *s, Error **errp)
960 s->s_accel = g_new0(SMMUv3AccelState, 1);
961 bs->iommu_ops = &smmuv3_accel_ops;
962 smmuv3_accel_as_init(s);
963 +
964 + if (s->s_accel->auto_mode) {
965 + s->machine_done.notify = smmuv3_accel_machine_done;
966 + qemu_add_machine_init_done_notifier(&s->machine_done);
967 + }
968 +
969 return true;
970 }
hw/arm/smmuv3-accel.h
+2
@@ -25,6 +25,8 @@ typedef struct SMMUv3AccelState {
25 uint32_t bypass_hwpt_id;
26 uint32_t abort_hwpt_id;
27 QLIST_HEAD(, SMMUv3AccelDevice) device_list;
28 + bool auto_mode;
29 + bool auto_finalised;
30 } SMMUv3AccelState;
31
32 typedef struct SMMUS1Hwpt {
include/hw/arm/smmuv3.h
+3
@@ -22,6 +22,7 @@
22 #include "hw/arm/smmu-common.h"
23 #include "qom/object.h"
24 #include "qapi/qapi-types-misc-arm.h"
25 +#include "qemu/notify.h"
26
27 #define TYPE_SMMUV3_IOMMU_MEMORY_REGION "smmuv3-iommu-memory-region"
28
@@ -74,6 +75,8 @@ struct SMMUv3State {
75 OnOffAuto ats;
76 OasMode oas;
77 SsidSizeMode ssidsize;
78 +
79 + Notifier machine_done;
80 };
81
82 typedef enum {