On a Wednesday in 2025, Nathan Chen via Devel wrote:
Introduce support for "pciBus" driver attribute for "smmuv3" IOMMU model. The "pciBus" attribute indicates the index of the controller that a smmuv3 IOMMU device is attached to, and differentiates the device-pluggable arm-smmuv3 model from the virt-machine-associated smmuv3 model.Signed-off-by: Nathan Chen <[email protected]> --- docs/formatdomain.rst | 4 ++ src/conf/domain_conf.c | 16 +++++++ src/conf/domain_conf.h | 1 + src/conf/domain_validate.c | 28 ++++++++++-- src/conf/schemas/domaincommon.rng | 5 ++ src/qemu/qemu_command.c | 76 ++++++++++++++++++++++++++++--- 6 files changed, 121 insertions(+), 9 deletions(-) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 4c245f41a9..a181462d13 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -9238,6 +9238,10 @@ Example: Enable x2APIC mode. Useful for higher number of guest CPUs. :since:`Since 11.5.0` (QEMU/KVM and ``amd`` model only) + ``pciBus`` + The ``pciBus`` attribute notes the index of the controller that an + IOMMU device is attached to. (QEMU/KVM and ``smmuv3`` model only) + The ``virtio`` IOMMU devices can further have ``address`` element as described in `Device addresses`_ (address has to by type of ``pci``). diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng index ae3fa95904..9afc679258 100644 --- a/src/conf/schemas/domaincommon.rng +++ b/src/conf/schemas/domaincommon.rng @@ -6322,6 +6322,11 @@ <ref name="virOnOff"/> </attribute> </optional> + <optional> + <attribute name="pciBus"> + <data type="unsignedInt"/> + </attribute> + </optional> </element> </optional> <optional> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 97fe4267ec..ad749afc41 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6239,6 +6239,62 @@ qemuBuildBootCommandLine(virCommand *cmd, } +static virJSONValue * +qemuBuildPCINestedSmmuv3DevProps(const virDomainDef *def, + const virDomainIOMMUDef *iommu, + size_t id) +{ + g_autoptr(virJSONValue) props = NULL; + g_autofree char *bus = NULL; + g_autofree char *smmuv3_id = NULL; + size_t i; +
+ for (i = 0; i < def->ncontrollers; i++) {
+ virDomainControllerDef *cont = def->controllers[i];
+ if (cont->idx == iommu->pci_bus) {
+ if (cont->type == VIR_DOMAIN_CONTROLLER_TYPE_PCI) {
+ const char *alias = cont->info.alias;
+
+ if (!alias)
+ return NULL;
+
+ if (virDomainDeviceAliasIsUserAlias(alias)) {
+ if (cont->model == VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT &&
+ iommu->pci_bus == 0) {
+ if (qemuDomainSupportsPCIMultibus(def))
+ bus = g_strdup("pci.0");
+ else
+ bus = g_strdup("pci");
+ } else if (cont->model ==
VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT) {
+ bus = g_strdup("pcie.0");
+ }
+ } else {
+ bus = g_strdup(alias);
+ }
+ break;
+ }
+ }
+ }
This duplicates parts of 'qemuBuildDeviceAddressPCIGetBus'
+
+ if (!bus) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Could not find a suitable controller for smmuv3."));
+ return NULL;
+ }
+
+ smmuv3_id = g_strdup_printf("smmuv3.%zu", id);
+
+ if (virJSONValueObjectAdd(&props,
+ "s:driver", "arm-smmuv3",
+ "s:primary-bus", bus,
+ "s:id", smmuv3_id,
+ NULL) < 0)
+ return NULL;
+
+ return g_steal_pointer(&props);
+}
+
+
static int
qemuBuildIOMMUCommandLine(virCommand *cmd,
const virDomainDef *def,
@@ -6286,9 +6342,6 @@ qemuBuildIOMMUCommandLine(virCommand *cmd,
return -1;
return 0;
- case VIR_DOMAIN_IOMMU_MODEL_SMMUV3:
- /* There is no -device for SMMUv3, so nothing to be done here */
- return 0;
case VIR_DOMAIN_IOMMU_MODEL_AMD:
if (virJSONValueObjectAdd(&wrapperProps,
@@ -6318,6 +6371,17 @@ qemuBuildIOMMUCommandLine(virCommand *cmd,
return 0;
+ case VIR_DOMAIN_IOMMU_MODEL_SMMUV3:
+ if (iommu->pci_bus >= 0) {
+ if (!(props = qemuBuildPCINestedSmmuv3DevProps(def, iommu, i)))
+ return -1;
+ if (qemuBuildDeviceCommandlineFromJSON(cmd, props, def, qemuCaps)
< 0)
+ return -1;
+ break;
+ } else {
+ return 0;
+ }
No need for the else branch.
+
case VIR_DOMAIN_IOMMU_MODEL_LAST:
default:
virReportEnumRangeError(virDomainIOMMUModel, iommu->model);
@@ -10822,15 +10886,15 @@ qemuBuildCommandLine(virDomainObj *vm,
if (qemuBuildBootCommandLine(cmd, def) < 0)
return NULL;
- if (qemuBuildIOMMUCommandLine(cmd, def, qemuCaps) < 0)
- return NULL;
-
if (qemuBuildGlobalControllerCommandLine(cmd, def) < 0)
return NULL;
if (qemuBuildControllersCommandLine(cmd, def, qemuCaps) < 0)
return NULL;
+ if (qemuBuildIOMMUCommandLine(cmd, def, qemuCaps) < 0)
+ return NULL;
+
Formatting the IOMMU devices after the controllers makes sense, but should be in a separate patch.
if (qemuBuildMemoryDeviceCommandLine(cmd, cfg, def, priv) < 0)
return NULL;
Reviewed-by: Ján Tomko <[email protected]> Jano
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