Re: [PATCH v2 06/23] xen/domctl: Add XEN_DOMCTL_CONFIG_VIOMMU_* and viommu config param

[Milan Djokic <milan_djokic@xxxxxxxx>]

On 3/25/26 19:52, Nick Rosbrook wrote:
> On Mon, Mar 23, 2026 at 6:51 PM Milan Djokic <milan_djokic@xxxxxxxx> wrote:
> > From: Rahul Singh <rahul.singh@xxxxxxx>
> >
> > Add new viommu_type field and field values XEN_DOMCTL_CONFIG_VIOMMU_NONE
> > XEN_DOMCTL_CONFIG_VIOMMU_SMMUV3 in xen_arch_domainconfig to
> > enable/disable vIOMMU support for domains.
> >
> > Also add viommu="N" parameter to xl domain configuration to enable the
> > vIOMMU for the domains. Currently, only the "smmuv3" type is supported
> > for ARM.
> >
> > Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
> > Signed-off-by: Milan Djokic <milan_djokic@xxxxxxxx>
> > ---
> >   docs/man/xl.cfg.5.pod.in             | 13 +++++++++++++
> >   tools/golang/xenlight/helpers.gen.go |  2 ++
> >   tools/golang/xenlight/types.gen.go   |  1 +
> >   tools/include/libxl.h                |  5 +++++
> >   tools/libs/light/libxl_arm.c         | 13 +++++++++++++
> >   tools/libs/light/libxl_types.idl     |  6 ++++++
> >   tools/xl/xl_parse.c                  |  9 +++++++++
> >   7 files changed, 49 insertions(+)
> >
> > diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
> > index 27c455210b..f69cdee55c 100644
> > --- a/docs/man/xl.cfg.5.pod.in
> > +++ b/docs/man/xl.cfg.5.pod.in
> > @@ -3162,6 +3162,19 @@ option.
> >
> >   =back
> >
> > +=over 4
> > +
> > +=item B<viommu="N">
> > +
> > +To enable viommu, user must specify the following option in the VM
> > +config file:
> > +
> > +viommu = "smmuv3"
> > +
> > +Currently, only the "smmuv3" type is supported for ARM.
> > +
> > +=back
> > +
> >   =head3 x86
> >
> >   =over 4
> > diff --git a/tools/golang/xenlight/helpers.gen.go 
> > b/tools/golang/xenlight/helpers.gen.go
> > index 8909fe8a1b..4f0997f02f 100644
> > --- a/tools/golang/xenlight/helpers.gen.go
> > +++ b/tools/golang/xenlight/helpers.gen.go
> > @@ -1195,6 +1195,7 @@ x.ArchArm.NrSpis = uint32(xc.arch_arm.nr_spis)
> >   if err := x.ArchArm.ArmSci.fromC(&xc.arch_arm.arm_sci);err != nil {
> >   return fmt.Errorf("converting field ArchArm.ArmSci: %v", err)
> >   }
> > +x.ArchArm.Viommu = ViommuType(xc.arch_arm.viommu)
> >   if err := x.ArchX86.MsrRelaxed.fromC(&xc.arch_x86.msr_relaxed);err != nil {
> >   return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err)
> >   }
> > @@ -1734,6 +1735,7 @@ xc.arch_arm.nr_spis = C.uint32_t(x.ArchArm.NrSpis)
> >   if err := x.ArchArm.ArmSci.toC(&xc.arch_arm.arm_sci); err != nil {
> >   return fmt.Errorf("converting field ArchArm.ArmSci: %v", err)
> >   }
> > +xc.arch_arm.viommu = C.libxl_viommu_type(x.ArchArm.Viommu)
> >   if err := x.ArchX86.MsrRelaxed.toC(&xc.arch_x86.msr_relaxed); err != nil {
> >   return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err)
> >   }
> > diff --git a/tools/golang/xenlight/types.gen.go 
> > b/tools/golang/xenlight/types.gen.go
> > index ab9d4ca7b4..8a37b52a82 100644
> > --- a/tools/golang/xenlight/types.gen.go
> > +++ b/tools/golang/xenlight/types.gen.go
> > @@ -610,6 +610,7 @@ Vuart VuartType
> >   SveVl SveType
> >   NrSpis uint32
> >   ArmSci ArmSci
> > +Viommu ViommuType
> >   }
> >   ArchX86 struct {
> >   MsrRelaxed Defbool
> The generated go code doesn't look right - it appears to be missing a
> definition for `ViommuType` and the associated constants for the
> "viommu_type" Enumeration added to libxl_types.idl. Does the code need
> re-generating?
Yes, I will re-generate the code in the updated version. Thanks for 
noticing.
> > diff --git a/tools/include/libxl.h b/tools/include/libxl.h
> > index bc35e412da..f7d5c77e23 100644
> > --- a/tools/include/libxl.h
> > +++ b/tools/include/libxl.h
> > @@ -318,6 +318,11 @@
> >    */
> >   #define LIBXL_HAVE_BUILDINFO_ARCH_ARM_SCI 1
> >
> > +/*
> > + * libxl_domain_build_info has the arch_arm.viommu_type field.
> > + */
> > +#define LIBXL_HAVE_BUILDINFO_ARM_VIOMMU 1
> > +
> >   /*
> >    * LIBXL_HAVE_SOFT_RESET indicates that libxl supports performing
> >    * 'soft reset' for domains and there is 'soft_reset' shutdown reason
> > diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
> > index 7e9f8a1bc3..a248793588 100644
> > --- a/tools/libs/light/libxl_arm.c
> > +++ b/tools/libs/light/libxl_arm.c
> > @@ -247,6 +247,19 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
> >       }
> >       LOG(DEBUG, " - SCI type=%u", config->arch.arm_sci_type);
> >
> > +    switch (d_config->b_info.arch_arm.viommu_type) {
> > +    case LIBXL_VIOMMU_TYPE_NONE:
> > +        config->arch.viommu_type = XEN_DOMCTL_CONFIG_VIOMMU_NONE;
> > +        break;
> > +    case LIBXL_VIOMMU_TYPE_SMMUV3:
> > +        config->arch.viommu_type = XEN_DOMCTL_CONFIG_VIOMMU_SMMUV3;
> > +        break;
> > +    default:
> > +        LOG(ERROR, "Unknown vIOMMU type %d",
> > +            d_config->b_info.arch_arm.viommu_type);
> > +        return ERROR_FAIL;
> > +    }
> > +
> >       return 0;
> >   }
> >
> > diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
> > index d64a573ff3..c7ad0e77b2 100644
> > --- a/tools/libs/light/libxl_types.idl
> > +++ b/tools/libs/light/libxl_types.idl
> > @@ -561,6 +561,11 @@ libxl_arm_sci = Struct("arm_sci", [
> >       ("type", libxl_arm_sci_type),
> >       ])
> >
> > +libxl_viommu_type = Enumeration("viommu_type", [
> > +    (0, "none"),
> > +    (1, "smmuv3")
> > +    ], init_val = "LIBXL_VIOMMU_TYPE_NONE")
> > +
> >   libxl_rdm_reserve = Struct("rdm_reserve", [
> >       ("strategy",    libxl_rdm_reserve_strategy),
> >       ("policy",      libxl_rdm_reserve_policy),
> > @@ -736,6 +741,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
> >                                  ("sve_vl", libxl_sve_type),
> >                                  ("nr_spis", uint32, {'init_val': 
> > 'LIBXL_NR_SPIS_DEFAULT'}),
> >                                  ("arm_sci", libxl_arm_sci),
> > +                               ("viommu_type", libxl_viommu_type),
> >                                 ])),
> >       ("arch_x86", Struct(None, [("msr_relaxed", libxl_defbool),
> >                                 ])),
> > diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
> > index 1a2ea8b5d5..dcae8314fe 100644
> > --- a/tools/xl/xl_parse.c
> > +++ b/tools/xl/xl_parse.c
> > @@ -3033,6 +3033,15 @@ skip_usbdev:
> >           }
> >       }
> >
> > +    if (!xlu_cfg_get_string (config, "viommu", &buf, 1)) {
> > +        e = libxl_viommu_type_from_string(buf, &b_info->arch_arm.viommu_type);
> > +        if (e) {
> > +            fprintf(stderr,
> > +                    "Unknown vIOMMU type \"%s\" specified\n", buf);
> > +            exit(-ERROR_FAIL);
> > +        }
> > +    }
> > +
> >       parse_vkb_list(config, d_config);
> >
> >       d_config->virtios = NULL;
> > --
> > 2.43.0
> -Nick
BR,
Milan